diff --git a/Notes/02_Working_with_data/01_Datatypes.md b/Notes/02_Working_with_data/01_Datatypes.md
index 60954ca..7d42dfd 100644
--- a/Notes/02_Working_with_data/01_Datatypes.md
+++ b/Notes/02_Working_with_data/01_Datatypes.md
@@ -1,4 +1,4 @@
-[Contents](../Contents.md) \| [Previous (1.6 Files)](../01_Introduction/06_Files.md) \| [Next (2.2 Containers)](02_Containers)
+[Contents](../Contents.md) \| [Previous (1.6 Files)](../01_Introduction/06_Files.md) \| [Next (2.2 Containers)](02_Containers.md)
 
 # 2.1 Datatypes and Data structures
 
@@ -446,4 +446,4 @@ dict_items([('name', 'AA'), ('shares', 75), ('price', 32.2), ('date', (6, 11, 20
 >>>
 ```
 
-[Contents](../Contents.md) \| [Previous (1.6 Files)](../01_Introduction/06_Files.md) \| [Next (2.2 Containers)](02_Containers)
+[Contents](../Contents.md) \| [Previous (1.6 Files)](../01_Introduction/06_Files.md) \| [Next (2.2 Containers)](02_Containers.md)
diff --git a/Notes/02_Working_with_data/02_Containers.md b/Notes/02_Working_with_data/02_Containers.md
index ff47922..53829c7 100644
--- a/Notes/02_Working_with_data/02_Containers.md
+++ b/Notes/02_Working_with_data/02_Containers.md
@@ -1,4 +1,4 @@
-[Contents](../Contents.md) \| [Previous (2.1 Datatypes)](01_Datatypes) \| [Next (2.3 Formatting)](03_Formatting)
+[Contents](../Contents.md) \| [Previous (2.1 Datatypes)](01_Datatypes.md) \| [Next (2.3 Formatting)](03_Formatting.md)
 
 # 2.2 Containers
 
@@ -442,5 +442,4 @@ should take the list of stocks in Exercise 2.5 and the dictionary of
 prices in Exercise 2.6 and computes the current value of the portfolio
 along with the gain/loss.
 
-[Contents](../Contents.md) \| [Previous (2.1 Datatypes)](01_Datatypes) \| [Next (2.3 Formatting)](03_Formatting)
-
+[Contents](../Contents.md) \| [Previous (2.1 Datatypes)](01_Datatypes.md) \| [Next (2.3 Formatting)](03_Formatting.md)
diff --git a/Notes/02_Working_with_data/03_Formatting.md b/Notes/02_Working_with_data/03_Formatting.md
index 02438e8..01e4d68 100644
--- a/Notes/02_Working_with_data/03_Formatting.md
+++ b/Notes/02_Working_with_data/03_Formatting.md
@@ -1,4 +1,4 @@
-[Contents](../Contents.md) \| [Previous (2.2 Containers)](02_Containers) \| [Next (2.4 Sequences)](04_Sequences)
+[Contents](../Contents.md) \| [Previous (2.2 Containers)](02_Containers.md) \| [Next (2.4 Sequences)](04_Sequences.md)
 
 # 2.3 Formatting
 
@@ -299,4 +299,4 @@ How would you modify your code so that the price includes the currency symbol ($
        IBM        100    $106.28      35.84
 ```
 
-[Contents](../Contents.md) \| [Previous (2.2 Containers)](02_Containers) \| [Next (2.4 Sequences)](04_Sequences)
+[Contents](../Contents.md) \| [Previous (2.2 Containers)](02_Containers.md) \| [Next (2.4 Sequences)](04_Sequences.md)
diff --git a/Notes/02_Working_with_data/04_Sequences.md b/Notes/02_Working_with_data/04_Sequences.md
index 2f3e1c2..c613d83 100644
--- a/Notes/02_Working_with_data/04_Sequences.md
+++ b/Notes/02_Working_with_data/04_Sequences.md
@@ -1,4 +1,4 @@
-[Contents](../Contents.md) \| [Previous (2.3 Formatting)](03_Formatting) \| [Next (2.5 Collections)](05_Collections)
+[Contents](../Contents.md) \| [Previous (2.3 Formatting)](03_Formatting.md) \| [Next (2.5 Collections)](05_Collections.md)
 
 # 2.4 Sequences
 
@@ -546,4 +546,4 @@ Also, be aware that `zip()` stops once the shortest input sequence is exhausted.
 >>>
 ```
 
-[Contents](../Contents.md) \| [Previous (2.3 Formatting)](03_Formatting) \| [Next (2.5 Collections)](05_Collections)
+[Contents](../Contents.md) \| [Previous (2.3 Formatting)](03_Formatting.md) \| [Next (2.5 Collections)](05_Collections.md)
diff --git a/Notes/02_Working_with_data/05_Collections.md b/Notes/02_Working_with_data/05_Collections.md
index d387be8..d558fd4 100644
--- a/Notes/02_Working_with_data/05_Collections.md
+++ b/Notes/02_Working_with_data/05_Collections.md
@@ -1,4 +1,4 @@
-[Contents](../Contents.md) \| [Previous (2.4 Sequences)](04_Sequences) \| [Next (2.6 List Comprehensions)](06_List_comprehension)
+[Contents](../Contents.md) \| [Previous (2.4 Sequences)](04_Sequences.md) \| [Next (2.6 List Comprehensions)](06_List_comprehension.md)
 
 # 2.5 collections module
 
@@ -168,4 +168,4 @@ in all of Python.  In fact, we could do an extended tutorial on just
 that.  However, doing so now would also be a distraction.  For now,
 put `collections` on your list of bedtime reading for later.
 
-[Contents](../Contents.md) \| [Previous (2.4 Sequences)](04_Sequences) \| [Next (2.6 List Comprehensions)](06_List_comprehension)
+[Contents](../Contents.md) \| [Previous (2.4 Sequences)](04_Sequences.md) \| [Next (2.6 List Comprehensions)](06_List_comprehension.md)
\ No newline at end of file
diff --git a/Notes/02_Working_with_data/06_List_comprehension.md b/Notes/02_Working_with_data/06_List_comprehension.md
index 9424176..18a3229 100644
--- a/Notes/02_Working_with_data/06_List_comprehension.md
+++ b/Notes/02_Working_with_data/06_List_comprehension.md
@@ -1,4 +1,4 @@
-[Contents](../Contents.md) \| [Previous (2.5 Collections)](05_Collections) \| [Next (2.7 Object Model)](07_Objects)
+[Contents](../Contents.md) \| [Previous (2.5 Collections)](05_Collections.md) \| [Next (2.7 Object Model)](07_Objects.md)
 
 # 2.6 List Comprehensions
 
@@ -326,4 +326,4 @@ extraction, and so forth.  Becoming a guru master of list
 comprehensions can substantially reduce the time spent devising a
 solution.  Also, don't forget about the `collections` module.
 
-[Contents](../Contents.md) \| [Previous (2.5 Collections)](05_Collections) \| [Next (2.7 Object Model)](07_Objects)
+[Contents](../Contents.md) \| [Previous (2.5 Collections)](05_Collections.md) \| [Next (2.7 Object Model)](07_Objects.md)
diff --git a/Notes/02_Working_with_data/07_Objects.md b/Notes/02_Working_with_data/07_Objects.md
index e914006..c357f41 100644
--- a/Notes/02_Working_with_data/07_Objects.md
+++ b/Notes/02_Working_with_data/07_Objects.md
@@ -1,4 +1,4 @@
-[Contents](../Contents.md) \| [Previous (2.6 List Comprehensions)](06_List_comprehension) \| [Next (3 Program Organization)](../03_Program_organization/00_Overview)
+[Contents](../Contents.md) \| [Previous (2.6 List Comprehensions)](06_List_comprehension.md) \| [Next (3 Program Organization)](../03_Program_organization/00_Overview.md)
 
 # 2.7 Objects
 
@@ -451,4 +451,4 @@ Bonus: How would you modify this example to additionally parse the
 Spend some time to ponder what you’ve done in this exercise. We’ll
 revisit these ideas a little later.
 
-[Contents](../Contents.md) \| [Previous (2.6 List Comprehensions)](06_List_comprehension) \| [Next (3 Program Organization)](../03_Program_organization/00_Overview)
+[Contents](../Contents.md) \| [Previous (2.6 List Comprehensions)](06_List_comprehension.md) \| [Next (3 Program Organization)](../03_Program_organization/00_Overview.md)
diff --git a/Notes/03_Program_organization/01_Script.md b/Notes/03_Program_organization/01_Script.md
index 9a8e154..07bc91d 100644
--- a/Notes/03_Program_organization/01_Script.md
+++ b/Notes/03_Program_organization/01_Script.md
@@ -1,4 +1,4 @@
-[Contents](../Contents.md) \| [Previous (2.7 Object Model)](../02_Working_with_data/07_Objects) \| [Next (3.2 More on Functions)](02_More_functions)
+[Contents](../Contents.md) \| [Previous (2.7 Object Model)](../02_Working_with_data/07_Objects.md) \| [Next (3.2 More on Functions)](02_More_functions.md)
 
 # 3.1 Scripting
 
@@ -299,4 +299,4 @@ you can.  At some point, that script is going to grow and you'll wish
 you had a bit more organization.  Also, a little known fact is that Python
 runs a bit faster if you use functions.
 
-[Contents](../Contents.md) \| [Previous (2.7 Object Model)](../02_Working_with_data/07_Objects) \| [Next (3.2 More on Functions)](02_More_functions)
+[Contents](../Contents.md) \| [Previous (2.7 Object Model)](../02_Working_with_data/07_Objects.md) \| [Next (3.2 More on Functions)](02_More_functions.md)
\ No newline at end of file
diff --git a/Notes/03_Program_organization/02_More_functions.md b/Notes/03_Program_organization/02_More_functions.md
index f49ba03..318ddc8 100644
--- a/Notes/03_Program_organization/02_More_functions.md
+++ b/Notes/03_Program_organization/02_More_functions.md
@@ -1,4 +1,4 @@
-[Contents](../Contents.md) \| [Previous (3.1 Scripting)](01_Script) \| [Next (3.3 Error Checking)](03_Error_checking)
+[Contents](../Contents.md) \| [Previous (3.1 Scripting)](01_Script.md) \| [Next (3.3 Error Checking)](03_Error_checking.md)
 
 # 3.2 More on Functions
 
@@ -513,4 +513,4 @@ select out columns of interest, perform type conversions, without
 having to worry too much about the inner workings of files or the
 `csv` module.
 
-[Contents](../Contents.md) \| [Previous (3.1 Scripting)](01_Script) \| [Next (3.3 Error Checking)](03_Error_checking)
+[Contents](../Contents.md) \| [Previous (3.1 Scripting)](01_Script.md) \| [Next (3.3 Error Checking)](03_Error_checking.md)
diff --git a/Notes/03_Program_organization/03_Error_checking.md b/Notes/03_Program_organization/03_Error_checking.md
index f722865..f403507 100644
--- a/Notes/03_Program_organization/03_Error_checking.md
+++ b/Notes/03_Program_organization/03_Error_checking.md
@@ -1,4 +1,4 @@
-[Contents](../Contents.md) \| [Previous (3.2 More on Functions)](02_More_functions) \| [Next (3.4 Modules)](04_Modules)
+[Contents](../Contents.md) \| [Previous (3.2 More on Functions)](02_More_functions.md) \| [Next (3.4 Modules)](04_Modules.md)
 
 # 3.3 Error Checking
 
@@ -402,4 +402,4 @@ most programs.  As a general rule, you shouldn’t silently ignore
 errors.  Instead, it’s better to report problems and to give the user
 an option to the silence the error message if they choose to do so.
 
-[Contents](../Contents.md) \| [Previous (3.2 More on Functions)](02_More_functions) \| [Next (3.4 Modules)](04_Modules)
+[Contents](../Contents.md) \| [Previous (3.2 More on Functions)](02_More_functions.md) \| [Next (3.4 Modules)](04_Modules.md)
diff --git a/Notes/03_Program_organization/04_Modules.md b/Notes/03_Program_organization/04_Modules.md
index 884635b..260f715 100644
--- a/Notes/03_Program_organization/04_Modules.md
+++ b/Notes/03_Program_organization/04_Modules.md
@@ -1,4 +1,4 @@
-[Contents](../Contents.md) \| [Previous (3.3 Error Checking)](03_Error_checking) \| [Next (3.5 Main Module)](05_Main_module)
+[Contents](../Contents.md) \| [Previous (3.3 Error Checking)](03_Error_checking.md) \| [Next (3.5 Main Module)](05_Main_module.md)
 
 # 3.4 Modules
 
@@ -338,4 +338,4 @@ also contains `read_portfolio()` and `read_prices()` functions.  And
 finally, `pcost.py` which computes the portfolio cost, but makes use
 of the `read_portfolio()` function written for the `report.py` program.
 
-[Contents](../Contents.md) \| [Previous (3.3 Error Checking)](03_Error_checking) \| [Next (3.5 Main Module)](05_Main_module)
+[Contents](../Contents.md) \| [Previous (3.3 Error Checking)](03_Error_checking.md) \| [Next (3.5 Main Module)](05_Main_module.md)
diff --git a/Notes/03_Program_organization/05_Main_module.md b/Notes/03_Program_organization/05_Main_module.md
index c8c75eb..55d711c 100644
--- a/Notes/03_Program_organization/05_Main_module.md
+++ b/Notes/03_Program_organization/05_Main_module.md
@@ -1,4 +1,4 @@
-[Contents](../Contents.md) \| [Previous (3.4 Modules)](04_Modules) \| [Next (3.6 Design Discussion)](06_Design_discussion)
+[Contents](../Contents.md) \| [Previous (3.4 Modules)](04_Modules.md) \| [Next (3.6 Design Discussion)](06_Design_discussion.md)
 
 # 3.5 Main Module
 
@@ -303,4 +303,4 @@ bash $ python3 pcost.py Data/portfolio.csv
 Total cost: 44671.15
 ```
 
-[Contents](../Contents.md) \| [Previous (3.4 Modules)](04_Modules) \| [Next (3.6 Design Discussion)](06_Design_discussion)
\ No newline at end of file
+[Contents](../Contents.md) \| [Previous (3.4 Modules)](04_Modules.md) \| [Next (3.6 Design Discussion)](06_Design_discussion.md)
\ No newline at end of file
diff --git a/Notes/03_Program_organization/06_Design_discussion.md b/Notes/03_Program_organization/06_Design_discussion.md
index 7a924af..5b18a6a 100644
--- a/Notes/03_Program_organization/06_Design_discussion.md
+++ b/Notes/03_Program_organization/06_Design_discussion.md
@@ -1,4 +1,4 @@
-[Contents](../Contents.md) \| [Previous (3.5 Main module)](05_Main_module) \| [Next (4 Classes)](../04_Classes_objects/00_Overview)
+[Contents](../Contents.md) \| [Previous (3.5 Main module)](05_Main_module.md) \| [Next (4 Classes)](../04_Classes_objects/00_Overview.md)
 
 # 3.6 Design Discussion
 
@@ -134,4 +134,4 @@ Fix the `read_portfolio()` and `read_prices()` functions in the
 Afterwards, your `report.py` and `pcost.py` programs should work
 the same way they always did.
 
-[Contents](../Contents.md) \| [Previous (3.5 Main module)](05_Main_module) \| [Next (4 Classes)](../04_Classes_objects/00_Overview)
\ No newline at end of file
+[Contents](../Contents.md) \| [Previous (3.5 Main module)](05_Main_module.md) \| [Next (4 Classes)](../04_Classes_objects/00_Overview.md)
\ No newline at end of file
diff --git a/Notes/04_Classes_objects/01_Class.md b/Notes/04_Classes_objects/01_Class.md
index 7ae03e7..c4d68dc 100644
--- a/Notes/04_Classes_objects/01_Class.md
+++ b/Notes/04_Classes_objects/01_Class.md
@@ -1,4 +1,4 @@
-[Contents](../Contents.md) \| [Previous (3.6 Design discussion)](../03_Program_organization/06_Design_discussion) \| [Next (4.2 Inheritance)](02_Inheritance)
+[Contents](../Contents.md) \| [Previous (3.6 Design discussion)](../03_Program_organization/06_Design_discussion.md) \| [Next (4.2 Inheritance)](02_Inheritance.md)
 
 # 4.1 Classes
 
@@ -295,4 +295,4 @@ You should be able to run your functions the same as before:
 >>>
 ```
 
-[Contents](../Contents.md) \| [Previous (3.6 Design discussion)](../03_Program_organization/06_Design_discussion) \| [Next (4.2 Inheritance)](02_Inheritance)
+[Contents](../Contents.md) \| [Previous (3.6 Design discussion)](../03_Program_organization/06_Design_discussion.md) \| [Next (4.2 Inheritance)](02_Inheritance.md)
diff --git a/Notes/04_Classes_objects/02_Inheritance.md b/Notes/04_Classes_objects/02_Inheritance.md
index d4a59fa..360635c 100644
--- a/Notes/04_Classes_objects/02_Inheritance.md
+++ b/Notes/04_Classes_objects/02_Inheritance.md
@@ -1,4 +1,4 @@
-[Contents](../Contents.md) \| [Previous (4.1 Classes)](01_Class) \| [Next (4.3 Special methods)](03_Special_methods)
+[Contents](../Contents.md) \| [Previous (4.1 Classes)](01_Class.md) \| [Next (4.3 Special methods)](03_Special_methods.md)
 
 # 4.2 Inheritance
 
@@ -624,4 +624,4 @@ on the topic of design patterns (although understanding what happened
 in this exercise will take you pretty far in terms of using objects in
 a practically useful way).
 
-[Contents](../Contents.md) \| [Previous (4.1 Classes)](01_Class) \| [Next (4.3 Special methods)](03_Special_methods)
+[Contents](../Contents.md) \| [Previous (4.1 Classes)](01_Class.md) \| [Next (4.3 Special methods)](03_Special_methods.md)
diff --git a/Notes/04_Classes_objects/03_Special_methods.md b/Notes/04_Classes_objects/03_Special_methods.md
index 0e219ca..460009e 100644
--- a/Notes/04_Classes_objects/03_Special_methods.md
+++ b/Notes/04_Classes_objects/03_Special_methods.md
@@ -1,4 +1,4 @@
-[Contents](../Contents.md) \| [Previous (4.2 Inheritance)](02_Inheritance) \| [Next (4.4 Exceptions)](04_Defining_exceptions)
+[Contents](../Contents.md) \| [Previous (4.2 Inheritance)](02_Inheritance.md) \| [Next (4.4 Exceptions)](04_Defining_exceptions.md)
 
 # 4.3 Special Methods
 
@@ -287,5 +287,5 @@ it should work:
 >>>
 ```
 
-[Contents](../Contents.md) \| [Previous (4.2 Inheritance)](02_Inheritance) \| [Next (4.4 Exceptions)](04_Defining_exceptions)
+[Contents](../Contents.md) \| [Previous (4.2 Inheritance)](02_Inheritance.md) \| [Next (4.4 Exceptions)](04_Defining_exceptions.md)
 
diff --git a/Notes/04_Classes_objects/04_Defining_exceptions.md b/Notes/04_Classes_objects/04_Defining_exceptions.md
index e0b9c41..a5777d7 100644
--- a/Notes/04_Classes_objects/04_Defining_exceptions.md
+++ b/Notes/04_Classes_objects/04_Defining_exceptions.md
@@ -1,4 +1,4 @@
-[Contents](../Contents.md) \| [Previous (4.3 Special methods)](03_Special_methods) \| [Next (5 Object Model)](../05_Object_model/00_Overview)
+[Contents](../Contents.md) \| [Previous (4.3 Special methods)](03_Special_methods.md) \| [Next (5 Object Model)](../05_Object_model/00_Overview.md)
 
 # 4.4 Defining Exceptions
 
@@ -51,4 +51,4 @@ FormatError: Unknown table format xls
 >>>
 ```
 
-[Contents](../Contents.md) \| [Previous (4.3 Special methods)](03_Special_methods) \| [Next (5 Object Model)](../05_Object_model/00_Overview)
+[Contents](../Contents.md) \| [Previous (4.3 Special methods)](03_Special_methods.md) \| [Next (5 Object Model)](../05_Object_model/00_Overview.md)
diff --git a/Notes/05_Object_model/01_Dicts_revisited.md b/Notes/05_Object_model/01_Dicts_revisited.md
index e7ebd87..e49a950 100644
--- a/Notes/05_Object_model/01_Dicts_revisited.md
+++ b/Notes/05_Object_model/01_Dicts_revisited.md
@@ -1,4 +1,4 @@
-[Contents](../Contents.md) \| [Previous (4.4 Exceptions)](../04_Classes_objects/04_Defining_exceptions) \| [Next (5.2 Encapsulation)](02_Classes_encapsulation)
+[Contents](../Contents.md) \| [Previous (4.4 Exceptions)](../04_Classes_objects/04_Defining_exceptions.md) \| [Next (5.2 Encapsulation)](02_Classes_encapsulation.md)
 
 # 5.1 Dictionaries Revisited
 
@@ -656,5 +656,4 @@ Here's how the `cost()` method of instance `n` above would be found:
 >>>
 ```
 
-[Contents](../Contents.md) \| [Previous (4.4 Exceptions)](../04_Classes_objects/04_Defining_exceptions) \| [Next (5.2 Encapsulation)](02_Classes_encapsulation)
-
+[Contents](../Contents.md) \| [Previous (4.4 Exceptions)](../04_Classes_objects/04_Defining_exceptions.md) \| [Next (5.2 Encapsulation)](02_Classes_encapsulation.md)
diff --git a/Notes/05_Object_model/02_Classes_encapsulation.md b/Notes/05_Object_model/02_Classes_encapsulation.md
index 339350e..07ea947 100644
--- a/Notes/05_Object_model/02_Classes_encapsulation.md
+++ b/Notes/05_Object_model/02_Classes_encapsulation.md
@@ -1,4 +1,4 @@
-[Contents](../Contents.md) \| [Previous (5.1 Dictionaries Revisited)](01_Dicts_revisited) \| [Next (6 Generators)](../06_Generators/00_Overview)
+[Contents](../Contents.md) \| [Previous (5.1 Dictionaries Revisited)](01_Dicts_revisited.md) \| [Next (6 Generators)](../06_Generators/00_Overview.md)
 
 # 5.2 Classes and Encapsulation
 
@@ -353,4 +353,4 @@ optimization on classes that serve as data structures.  Using slots
 will make such programs use far-less memory and run a bit faster.
 You should probably avoid `__slots__` on most other classes however.
 
-[Contents](../Contents.md) \| [Previous (5.1 Dictionaries Revisited)](01_Dicts_revisited) \| [Next (6 Generators)](../06_Generators/00_Overview)
+[Contents](../Contents.md) \| [Previous (5.1 Dictionaries Revisited)](01_Dicts_revisited.md) \| [Next (6 Generators)](../06_Generators/00_Overview.md)
diff --git a/Notes/06_Generators/01_Iteration_protocol.md b/Notes/06_Generators/01_Iteration_protocol.md
index 2de2e8b..c22fab6 100644
--- a/Notes/06_Generators/01_Iteration_protocol.md
+++ b/Notes/06_Generators/01_Iteration_protocol.md
@@ -1,4 +1,4 @@
-[Contents](../Contents.md) \| [Previous (5.2 Encapsulation)](../05_Object_model/02_Classes_encapsulation) \| [Next (6.2 Customizing Iteration)](02_Customizing_iteration)
+[Contents](../Contents.md) \| [Previous (5.2 Encapsulation)](../05_Object_model/02_Classes_encapsulation.md) \| [Next (6.2 Customizing Iteration)](02_Customizing_iteration.md)
 
 # 6.1 Iteration Protocol
 
@@ -314,4 +314,4 @@ Python normally work.  For container objects, supporting iteration,
 indexing, containment, and other kinds of operators is an important
 part of this.
 
-[Contents](../Contents.md) \| [Previous (5.2 Encapsulation)](../05_Object_model/02_Classes_encapsulation) \| [Next (6.2 Customizing Iteration)](02_Customizing_iteration)
+[Contents](../Contents.md) \| [Previous (5.2 Encapsulation)](../05_Object_model/02_Classes_encapsulation.md) \| [Next (6.2 Customizing Iteration)](02_Customizing_iteration.md)
\ No newline at end of file
diff --git a/Notes/06_Generators/02_Customizing_iteration.md b/Notes/06_Generators/02_Customizing_iteration.md
index 8f9faeb..bd95c6a 100644
--- a/Notes/06_Generators/02_Customizing_iteration.md
+++ b/Notes/06_Generators/02_Customizing_iteration.md
@@ -1,4 +1,4 @@
-[Contents](../Contents.md) \| [Previous (6.1 Iteration Protocol)](01_Iteration_protocol) \| [Next (6.3 Producer/Consumer)](03_Producers_consumers)
+[Contents](../Contents.md) \| [Previous (6.1 Iteration Protocol)](01_Iteration_protocol.md) \| [Next (6.3 Producer/Consumer)](03_Producers_consumers.md)
 
 # 6.2 Customizing Iteration
 
@@ -267,4 +267,4 @@ is now this completely general purpose utility that you can use in any program.
 example, you could use it to watch server logs, debugging logs, and other similar data sources.
 That's kind of cool.
 
-[Contents](../Contents.md) \| [Previous (6.1 Iteration Protocol)](01_Iteration_protocol) \| [Next (6.3 Producer/Consumer)](03_Producers_consumers)
+[Contents](../Contents.md) \| [Previous (6.1 Iteration Protocol)](01_Iteration_protocol.md) \| [Next (6.3 Producer/Consumer)](03_Producers_consumers.md)
\ No newline at end of file
diff --git a/Notes/06_Generators/03_Producers_consumers.md b/Notes/06_Generators/03_Producers_consumers.md
index 27cb453..2849862 100644
--- a/Notes/06_Generators/03_Producers_consumers.md
+++ b/Notes/06_Generators/03_Producers_consumers.md
@@ -1,4 +1,4 @@
-[Contents](../Contents.md) \| [Previous (6.2 Customizing Iteration)](02_Customizing_iteration) \| [Next (6.4 Generator Expressions)](04_More_generators)
+[Contents](../Contents.md) \| [Previous (6.2 Customizing Iteration)](02_Customizing_iteration.md) \| [Next (6.4 Generator Expressions)](04_More_generators.md)
 
 # 6.3 Producers, Consumers and Pipelines
 
@@ -299,6 +299,4 @@ pipelines.  In addition, you can create functions that package a
 series of pipeline stages into a single function call (for example,
 the `parse_stock_data()` function).
 
-[Contents](../Contents.md) \| [Previous (6.2 Customizing Iteration)](02_Customizing_iteration) \| [Next (6.4 Generator Expressions)](04_More_generators)
-
-
+[Contents](../Contents.md) \| [Previous (6.2 Customizing Iteration)](02_Customizing_iteration.md) \| [Next (6.4 Generator Expressions)](04_More_generators.md)
diff --git a/Notes/06_Generators/04_More_generators.md b/Notes/06_Generators/04_More_generators.md
index 7b2517f..41cdfc4 100644
--- a/Notes/06_Generators/04_More_generators.md
+++ b/Notes/06_Generators/04_More_generators.md
@@ -1,4 +1,4 @@
-[Contents](../Contents.md) \| [Previous (6.3 Producer/Consumer)](03_Producers_consumers) \| [Next (7 Advanced Topics)](../07_Advanced_Topics/00_Overview)
+[Contents](../Contents.md) \| [Previous (6.3 Producer/Consumer)](03_Producers_consumers.md) \| [Next (7 Advanced Topics)](../07_Advanced_Topics/00_Overview.md)
 
 # 6.4 More Generators
 
@@ -180,4 +180,4 @@ Modify the `ticker.py` program to use generator expressions
 as appropriate.
 
 
-[Contents](../Contents.md) \| [Previous (6.3 Producer/Consumer)](03_Producers_consumers) \| [Next (7 Advanced Topics)](../07_Advanced_Topics/00_Overview)
\ No newline at end of file
+[Contents](../Contents.md) \| [Previous (6.3 Producer/Consumer)](03_Producers_consumers.md) \| [Next (7 Advanced Topics)](../07_Advanced_Topics/00_Overview.md)
diff --git a/Notes/07_Advanced_Topics/01_Variable_arguments.md b/Notes/07_Advanced_Topics/01_Variable_arguments.md
index 53affe7..f0e82f4 100644
--- a/Notes/07_Advanced_Topics/01_Variable_arguments.md
+++ b/Notes/07_Advanced_Topics/01_Variable_arguments.md
@@ -1,5 +1,5 @@
 
-[Contents](../Contents.md) \| [Previous (6.4 Generator Expressions)](../06_Generators/04_More_generators) \| [Next (7.2 Anonymous Functions)](02_Anonymous_function)
+[Contents](../Contents.md) \| [Previous (6.4 Generator Expressions)](../06_Generators/04_More_generators.md) \| [Next (7.2 Anonymous Functions)](02_Anonymous_function.md)
 
 # 7.1 Variable Arguments
 
@@ -230,4 +230,4 @@ Now, try silencing the errors:
 >>>
 ```
 
-[Contents](../Contents.md) \| [Previous (6.4 Generator Expressions)](../06_Generators/04_More_generators) \| [Next (7.2 Anonymous Functions)](02_Anonymous_function)
+[Contents](../Contents.md) \| [Previous (6.4 Generator Expressions)](../06_Generators/04_More_generators.md) \| [Next (7.2 Anonymous Functions)](02_Anonymous_function.md)
\ No newline at end of file
diff --git a/Notes/07_Advanced_Topics/02_Anonymous_function.md b/Notes/07_Advanced_Topics/02_Anonymous_function.md
index 53c739c..51d4b9b 100644
--- a/Notes/07_Advanced_Topics/02_Anonymous_function.md
+++ b/Notes/07_Advanced_Topics/02_Anonymous_function.md
@@ -1,4 +1,4 @@
-[Contents](../Contents.md) \| [Previous (7.1 Variable Arguments)](01_Variable_arguments) \| [Next (7.3 Returning Functions)](03_Returning_functions)
+[Contents](../Contents.md) \| [Previous (7.1 Variable Arguments)](01_Variable_arguments.md) \| [Next (7.3 Returning Functions)](03_Returning_functions.md)
 
 # 7.2 Anonymous Functions and Lambda
 
@@ -165,4 +165,4 @@ Note: `lambda` is a useful shortcut because it allows you to
 define a special processing function directly in the call to `sort()` as
 opposed to having to define a separate function first.
 
-[Contents](../Contents.md) \| [Previous (7.1 Variable Arguments)](01_Variable_arguments) \| [Next (7.3 Returning Functions)](03_Returning_functions)
+[Contents](../Contents.md) \| [Previous (7.1 Variable Arguments)](01_Variable_arguments.md) \| [Next (7.3 Returning Functions)](03_Returning_functions.md)
diff --git a/Notes/07_Advanced_Topics/03_Returning_functions.md b/Notes/07_Advanced_Topics/03_Returning_functions.md
index c6eb932..30e6f07 100644
--- a/Notes/07_Advanced_Topics/03_Returning_functions.md
+++ b/Notes/07_Advanced_Topics/03_Returning_functions.md
@@ -1,4 +1,4 @@
-[Contents](../Contents.md) \| [Previous (7.2 Anonymous Functions)](02_Anonymous_function) \| [Next (7.4 Decorators)](04_Function_decorators)
+[Contents](../Contents.md) \| [Previous (7.2 Anonymous Functions)](02_Anonymous_function.md) \| [Next (7.4 Decorators)](04_Function_decorators.md)
 
 # 7.3 Returning Functions
 
@@ -237,4 +237,4 @@ is often good.
 Rewrite the `Stock` class in the file `stock.py` so that it uses typed properties
 as shown.
 
-[Contents](../Contents.md) \| [Previous (7.2 Anonymous Functions)](02_Anonymous_function) \| [Next (7.4 Decorators)](04_Function_decorators)
+[Contents](../Contents.md) \| [Previous (7.2 Anonymous Functions)](02_Anonymous_function.md) \| [Next (7.4 Decorators)](04_Function_decorators.md)
diff --git a/Notes/07_Advanced_Topics/04_Function_decorators.md b/Notes/07_Advanced_Topics/04_Function_decorators.md
index dc98794..ed96ab5 100644
--- a/Notes/07_Advanced_Topics/04_Function_decorators.md
+++ b/Notes/07_Advanced_Topics/04_Function_decorators.md
@@ -1,4 +1,4 @@
-[Contents](../Contents.md) \| [Previous (7.3 Returning Functions)](03_Returning_functions) \| [Next (7.5 Decorated Methods)](05_Decorated_methods)
+[Contents](../Contents.md) \| [Previous (7.3 Returning Functions)](03_Returning_functions.md) \| [Next (7.5 Decorated Methods)](05_Decorated_methods.md)
 
 # 7.4 Function Decorators
 
@@ -157,4 +157,4 @@ Discussion:  This `@timethis` decorator can be placed in front of any
 function definition.   Thus, you might use it as a diagnostic tool for
 performance tuning.
 
-[Contents](../Contents.md) \| [Previous (7.3 Returning Functions)](03_Returning_functions) \| [Next (7.5 Decorated Methods)](05_Decorated_methods)
+[Contents](../Contents.md) \| [Previous (7.3 Returning Functions)](03_Returning_functions.md) \| [Next (7.5 Decorated Methods)](05_Decorated_methods.md)
diff --git a/Notes/07_Advanced_Topics/05_Decorated_methods.md b/Notes/07_Advanced_Topics/05_Decorated_methods.md
index e74a031..4a13aae 100644
--- a/Notes/07_Advanced_Topics/05_Decorated_methods.md
+++ b/Notes/07_Advanced_Topics/05_Decorated_methods.md
@@ -1,4 +1,4 @@
-[Contents](../Contents.md) \| [Previous (7.4 Decorators)](04_Function_decorators) \| [Next (8 Testing and Debugging)](../08_Testing_debugging/00_Overview)
+[Contents](../Contents.md) \| [Previous (7.4 Decorators)](04_Function_decorators.md) \| [Next (8 Testing and Debugging)](../08_Testing_debugging/00_Overview.md)
 
 # 7.5 Decorated Methods
 
@@ -208,4 +208,4 @@ To use this new Portfolio class, you can now write code like this:
 Make these changes to the `Portfolio` class and modify the `report.py`
 code to use the class method.
 
-[Contents](../Contents.md) \| [Previous (7.4 Decorators)](04_Function_decorators) \| [Next (8 Testing and Debugging)](../08_Testing_debugging/00_Overview)
+[Contents](../Contents.md) \| [Previous (7.4 Decorators)](04_Function_decorators.md) \| [Next (8 Testing and Debugging)](../08_Testing_debugging/00_Overview.md)
diff --git a/Notes/08_Testing_debugging/01_Testing.md b/Notes/08_Testing_debugging/01_Testing.md
index 493368a..f1138bf 100644
--- a/Notes/08_Testing_debugging/01_Testing.md
+++ b/Notes/08_Testing_debugging/01_Testing.md
@@ -1,4 +1,4 @@
-[Contents](../Contents.md) \| [Previous (7.5 Decorated Methods)](../07_Advanced_Topics/05_Decorated_methods) \| [Next (8.2 Logging)](02_Logging)
+[Contents](../Contents.md) \| [Previous (7.5 Decorated Methods)](../07_Advanced_Topics/05_Decorated_methods.md) \| [Next (8.2 Logging)](02_Logging.md)
 
 # 8.1 Testing
 
@@ -290,4 +290,4 @@ class TestStock(unittest.TestCase):
              s.shares = '100'
 ```
 
-[Contents](../Contents.md) \| [Previous (7.5 Decorated Methods)](../07_Advanced_Topics/05_Decorated_methods) \| [Next (8.2 Logging)](02_Logging)
+[Contents](../Contents.md) \| [Previous (7.5 Decorated Methods)](../07_Advanced_Topics/05_Decorated_methods.md) \| [Next (8.2 Logging)](02_Logging.md)
diff --git a/Notes/08_Testing_debugging/02_Logging.md b/Notes/08_Testing_debugging/02_Logging.md
index c320818..30243a7 100644
--- a/Notes/08_Testing_debugging/02_Logging.md
+++ b/Notes/08_Testing_debugging/02_Logging.md
@@ -1,4 +1,4 @@
-[Contents](../Contents.md) \| [Previous (8.1 Testing)](01_Testing) \| [Next (8.3 Debugging)](03_Debugging)
+[Contents](../Contents.md) \| [Previous (8.1 Testing)](01_Testing.md) \| [Next (8.3 Debugging)](03_Debugging.md)
 
 # 8.2 Logging
 
@@ -306,4 +306,4 @@ logging.basicConfig(
 Again, you'd need to put this someplace in the startup steps of your
 program.  For example, where would you put this in your `report.py` program?
 
-[Contents](../Contents.md) \| [Previous (8.1 Testing)](01_Testing) \| [Next (8.3 Debugging)](03_Debugging)
+[Contents](../Contents.md) \| [Previous (8.1 Testing)](01_Testing.md) \| [Next (8.3 Debugging)](03_Debugging.md)
diff --git a/Notes/08_Testing_debugging/03_Debugging.md b/Notes/08_Testing_debugging/03_Debugging.md
index 445c94d..378a6a3 100644
--- a/Notes/08_Testing_debugging/03_Debugging.md
+++ b/Notes/08_Testing_debugging/03_Debugging.md
@@ -1,4 +1,4 @@
-[Contents](../Contents.md) \| [Previous (8.2 Logging)](02_Logging) \| [Next (9 Packages)](../09_Packages/00_Overview)
+[Contents](../Contents.md) \| [Previous (8.2 Logging)](02_Logging.md) \| [Next (9 Packages)](../09_Packages/00_Overview.md)
 
 # 8.3 Debugging
 
@@ -158,4 +158,4 @@ For breakpoints location is one of the following.
 
 It runs. Ship it!
 
-[Contents](../Contents.md) \| [Previous (8.2 Logging)](02_Logging) \| [Next (9 Packages)](../09_Packages/00_Overview)
+[Contents](../Contents.md) \| [Previous (8.2 Logging)](02_Logging.md) \| [Next (9 Packages)](../09_Packages/00_Overview.md)
diff --git a/Notes/09_Packages/01_Packages.md b/Notes/09_Packages/01_Packages.md
index 8d844da..24fcb35 100644
--- a/Notes/09_Packages/01_Packages.md
+++ b/Notes/09_Packages/01_Packages.md
@@ -1,4 +1,4 @@
-[Contents](../Contents.md) \| [Previous (8.3 Debugging)](../08_Testing_debugging/03_Debugging) \| [Next (9.2 Third Party Packages)](02_Third_party.md)
+[Contents](../Contents.md) \| [Previous (8.3 Debugging)](../08_Testing_debugging/03_Debugging.md) \| [Next (9.2 Third Party Packages)](02_Third_party.md)
 
 # 9.1 Packages
 
@@ -441,4 +441,4 @@ porty-app/
         typedproperty.py
 ```
 
-[Contents](../Contents.md) \| [Previous (8.3 Debugging)](../08_Testing_debugging/03_Debugging) \| [Next (9.2 Third Party Packages)](02_Third_party.md)
+[Contents](../Contents.md) \| [Previous (8.3 Debugging)](../08_Testing_debugging/03_Debugging.md) \| [Next (9.2 Third Party Packages)](02_Third_party.md)
diff --git a/Notes/09_Packages/02_Third_party.md b/Notes/09_Packages/02_Third_party.md
index 04ebb2c..2fa5e55 100644
--- a/Notes/09_Packages/02_Third_party.md
+++ b/Notes/09_Packages/02_Third_party.md
@@ -1,4 +1,4 @@
-[Contents](../Contents.md) \| [Previous (9.1 Packages)](01_Packages) \| [Next (9.3 Distribution)](03_Distribution)
+[Contents](../Contents.md) \| [Previous (9.1 Packages)](01_Packages.md) \| [Next (9.3 Distribution)](03_Distribution.md)
 
 # 9.2 Third Party Modules
 
@@ -135,7 +135,7 @@ I refer you to the [Python Packaging User Guide](https://packaging.python.org).
 See if you can recreate the steps of making a virtual environment and installing
 pandas into it as shown above.
 
-[Contents](../Contents.md) \| [Previous (9.1 Packages)](01_Packages) \| [Next (9.3 Distribution)](03_Distribution)
+[Contents](../Contents.md) \| [Previous (9.1 Packages)](01_Packages.md) \| [Next (9.3 Distribution)](03_Distribution.md)