diff --git a/books/free-programming-books-langs.md b/books/free-programming-books-langs.md
index 1d2934f9b..081848307 100644
--- a/books/free-programming-books-langs.md
+++ b/books/free-programming-books-langs.md
@@ -241,7 +241,7 @@ Books on general-purpose programming that don't focus on a specific language are
 
 * [A Guide to Ada for C and C++ Programmers](http://www.cs.uni.edu/~mccormic/4740/guide-c2ada.pdf) (PDF)
 * [Ada Distilled](http://www.adapower.com/pdfs/AdaDistilled07-27-2003.pdf) (PDF)
-* [Ada for the C++ or Java Developer](https://www.adacore.com/uploads/books/pdf/Ada_for_the_C_or_Java_Developer-cc.pdf) - Quentin Ochem (PDF)
+* [Ada for the C++ or Java Developer](https://www.adacore.com/uploads/books/pdf/Ada_for_the_C_or_Java_Developer-cc.pdf) - Quentin Ochem (PDF) (CC BY-NC-SA)
 * [Ada Programming](https://en.wikibooks.org/wiki/Ada_Programming) - Wikibooks
 * [Ada Reference Manual - ISO/IEC 8652:2012(E) Language and Standard Libraries](http://www.ada-auth.org/standards/12rm/RM-Final.pdf) (PDF)
 * [Introduction To Ada](https://learn.adacore.com/courses/intro-to-ada/index.html)
@@ -300,7 +300,7 @@ Books on general-purpose programming that don't focus on a specific language are
 * [Introduction to Arduino](http://playground.arduino.cc/Main/ManualsAndCurriculum)
 * [Introduction to Arduino : A piece of cake!](http://www.introtoarduino.com) - Alan G. Smith
 * [Learn Arduino](https://riptutorial.com/Download/arduino.pdf) - Compiled from StackOverflow documentation (PDF)
-* [Open softwear - Fashionable prototyping and wearable computing using the Arduino](https://softwear.cc/book/files/Open_Softwear-beta090712.pdf) - Tony Olsson, David Gaetano, Jonas Odhner, Samson Wiklund (PDF)
+* [Open softwear - Fashionable prototyping and wearable computing using the Arduino](https://softwear.cc/book/files/Open_Softwear-beta090712.pdf) - Tony Olsson, David Gaetano, Jonas Odhner, Samson Wiklund (PDF) (CC BY-NC-ND)
 
 
 ### ASP.NET
@@ -354,7 +354,7 @@ Books on general-purpose programming that don't focus on a specific language are
 * [Easy 6502](http://skilldrick.github.io/easy6502/) - Nick Morgan
 * [Machine Language for Beginners](https://archive.org/details/ataribooks-machine-language-for-beginners) - Richard Mansfield
 * [MIPS Assembly Language Programming Using QtSpim](http://www.egr.unlv.edu/~ed/MIPStextSMv11.pdf) - Ed Jorgensen (PDF)
-* [Programmed Introduction to MIPS Assembly Language](http://chortle.ccsu.edu/AssemblyTutorial/index.html)
+* [Programmed Introduction to MIPS Assembly Language](http://chortle.ccsu.edu/AssemblyTutorial/index.html) (CC BY-NC)
 * [The Second Book of Machine Language](http://www.atariarchives.org/2bml/)