diff --git a/books/free-programming-books-subjects.md b/books/free-programming-books-subjects.md
index ed2630ddc..ed5193e5b 100644
--- a/books/free-programming-books-subjects.md
+++ b/books/free-programming-books-subjects.md
@@ -161,11 +161,11 @@ Books that cover a specific programming language can be found in the [BY PROGRAM
 * [Build a Blockchain from Scratch in Go with gRPC](https://github.com/volodymyrprokopyuk/go-blockchain) - Volodymyr Prokopyuk
 * [chain.courses](https://web.archive.org/web/20220127020549/https://chain.courses/) - James Gan, Rishub Kumar *(:card_file_box: archived)*
 * [Getting Started with Enterprise Blockchain: A Guide to Design and Development](https://www.ibm.com/downloads/cas/RYWXAR0M) - Michael Bradley, David Gorman, Matt Lucas, Matthew Golby-Kirk (PDF)
-* [Grokking Bitcoin](https://rosenbaum.se/book/) - Kalle Rosenbaum (HTML)
+* [Grokking Bitcoin](https://rosenbaum.se/book/) - Kalle Rosenbaum (HTML) `(CC BY-NC-SA)`
 * [IBM Blockchain: The Founder’s Handbook, Third Edition](https://www.ibm.com/downloads/cas/GZPPMWM5) - Antonio Banda, Matthew Hamilton, Eileen Lowry, John Widdifield, et al. (PDF)
 * [Learning Bitcoin from the Command Line](https://github.com/BlockchainCommons/Learning-Bitcoin-from-the-Command-Line) - Christopher Allen, Shannon Appelcline, et al. (HTML)
-* [Mastering Bitcoin - Unlocking digital currencies (2017), 2nd Edition](https://github.com/bitcoinbook/bitcoinbook) - Andreas M. Antonopoulos (AsciiDoc)
-* [Mastering Ethereum (2018), 1st Edition](https://github.com/ethereumbook/ethereumbook) - Andreas M. Antonopoulos, Gavin Wood (AsciiDoc)
+* [Mastering Bitcoin - Unlocking digital currencies (2017), 2nd Edition](https://github.com/bitcoinbook/bitcoinbook) - Andreas M. Antonopoulos (AsciiDoc) `(CC BY-NC-ND)`
+* [Mastering Ethereum (2018), 1st Edition](https://github.com/ethereumbook/ethereumbook) - Andreas M. Antonopoulos, Gavin Wood (AsciiDoc) 
 * [Mastering the Lightning Network](https://github.com/lnbook/lnbook) - Andreas M. Antonopoulos, Olaoluwa Osuntokun, Rene Pickhardt (AsciiDoc)
 * [Playtime with Hyperledger Composer](https://schadokar.dev/ebooks/playtime-with-hyperledger-composer/) - Shubham Chadokar (PDF)
 
@@ -200,7 +200,7 @@ Books that cover a specific programming language can be found in the [BY PROGRAM
 
 ### Competitive Programming
 
-* [Competitive Programmer's Handbook](https://cses.fi/book/book.pdf) - Antti Laaksonen (PDF)
+* [Competitive Programmer's Handbook](https://cses.fi/book/book.pdf) - Antti Laaksonen (PDF) `(CC BY-NC-SA)`
 * [Competitive Programming, 1st Edition](https://cpbook.net/#CP1details) - Steven Halim [(PDF)](https://www.comp.nus.edu.sg/~stevenha/myteaching/competitive_programming/cp1.pdf)
 * [Competitive Programming, 2nd Edition](https://cpbook.net/#CP2details) - Steven Halim [(PDF)](https://www.comp.nus.edu.sg/~stevenha/myteaching/competitive_programming/cp2.pdf)
 * [Principles of Algorithmic Problem Solving](https://www.csc.kth.se/~jsannemo/slask/main.pdf) - Johan Sannemo (PDF)