Continue reformatting part 3 (#109)

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* remove examples (with code)

* update readme

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* move material to appendix

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* example from Li-yao Xia

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README.md

@@ -16,9 +16,9 @@ The book is a tutorial exposition of the theoretical knowledge that functional p
 
 ## Related video presentations
 
-[What I learned about functional programming while writing a book about it (extended version)](https://youtu.be/T5oB8PZQNvY)
+[Playlist: Lectures on relational parametricity](https://www.youtube.com/watch?v=Jf2VFB90Q0s&list=PLcoadSpY7rHUO0I1zdcbu9EeByYbwPSQ6&ab_channel=SergeiWinitzki)
 
-[Explaining "theorems for free" and parametricity](https://youtu.be/nSyG5USX3-c)
+[What I learned about functional programming while writing a book about it (extended version)](https://youtu.be/T5oB8PZQNvY)
 
 [Explaining Curry-Howard correspondence](https://youtu.be/XYs1Xg1JbVY)
 
@@ -28,8 +28,6 @@ The book is a tutorial exposition of the theoretical knowledge that functional p
 
 [What did category theory ever do for us (functional programmers)](https://www.youtube.com/watch?v=Zau8CxsfxOo)
 
-[Parametricity properties of purely functional code](https://youtu.be/vTWLtBTEmAY)
-
 [Playlist: Functional programming tutorials](https://www.youtube.com/playlist?list=PLcoadSpY7rHXJWbUkjQ3P9MXBbXxLP8kV)
 contains audio recordings with slides. The tutorials show an early version of the material in this book.
 Many notations and explanations have been revised and improved when writing up the text of the book.
@@ -43,7 +41,7 @@ For those unfamiliar with the GNU FDL: this means the book is free (as in "freed
 
 This `git` repository
 contains the full source code for the book (LyX / LaTeX / jpg / pdf) and shell scripts for building a PDF version of the book.
-So, this is a "transparent" copy in the sense of the GNU license; the source code of the book is in a format that is convenient to use and to modify.
+So, this is a "transparent" copy in the sense of the GNU license: the source code of the book is in a format that is convenient to use and to modify.
 
 The ["Releases" section](https://github.com/winitzki/sofp/releases) of this repository contains (under "Assets") the full uncorrected draft (`sofp.pdf`)
 and the finished and proof-read part of the draft (`sofp-draft.pdf`).
@@ -59,11 +57,17 @@ The talk slides are not part of the book and are partially obsolete both in cont
 
 # Current status of the book
 
-Chapters 1-12 and 14, as well as appendices and discussion chapters are ready after a second proofreading of the draft.
+The book is split into three volumes, corresponding to the three parts ranged by difficulty.
+
+Volume 1 (Chapters 1-5) and Volume 2 (Chapters 6-12) are ready. Volume 3 is still in the works.
+
+[Volume 1 on Amazon](https://www.amazon.com/Science-Functional-Programming-Part-tutorial/dp/1471040046/)
+
+[Volume 2 on Amazon](https://www.amazon.com/dp/144619146X/)
 
-Chapter 13 remains under construction. It is the last chapter to be written. After that, the book will be ready for general release. 
+Chapter 13 in Volume 3 remains under construction. It is the last chapter to be written. After that, the book will be ready for general release. 
 
-# Leanpub version of the draft
+# Leanpub version of the full draft
 
 The draft version is [available for purchase on leanpub](https://leanpub.com/sofp) for people who want to be notified about updates.