diff --git a/books/free-programming-books-langs.md b/books/free-programming-books-langs.md
index 3202042b76744..d800e3842a8a2 100644
--- a/books/free-programming-books-langs.md
+++ b/books/free-programming-books-langs.md
@@ -827,8 +827,8 @@ Books on general-purpose programming that don't focus on a specific language are
 * [How To Code in Go](https://www.digitalocean.com/community/books/how-to-code-in-go-ebook) - Mark Bates, Cory Lanou, Timothy J. Raymond (PDF, EPUB)
 * [Learn Go in Y minutes](https://learnxinyminutes.com/docs/go/)
 * [Learn Go with Tests](https://quii.gitbook.io/learn-go-with-tests/) - Chris James
-* [Learning Go](https://miek.nl/go/)
-* [Let's learn Go!](http://go-book.readthedocs.io/en/latest/)
+* [Learning Go](https://miek.nl/go/) (CC BY-NC-SA)
+* [Let's learn Go!](http://go-book.readthedocs.io/en/latest/) (CC BY-NC-SA)
 * [Practical Cryptography With Go](https://leanpub.com/gocrypto/read) - Kyle Isom
 * [Practical Go Lessons](https://www.practical-go-lessons.com) - Maximilien Andile
 * [Practical Go: Real world advice for writing maintainable Go programs](https://dave.cheney.net/practical-go/presentations/qcon-china.html) - Dave Cheney (HTML)
@@ -842,9 +842,9 @@ Books on general-purpose programming that don't focus on a specific language are
 
 #### GraphQL
 
-* [Fullstack GraphQL](https://github.com/GraphQLCollege/fullstack-graphql)
+* [Fullstack GraphQL](https://github.com/GraphQLCollege/fullstack-graphql) (CC BY-NC-SA)
 * [GraphQL or Bust](https://nordicapis.com/wp-content/uploads/GraphQL-or-Bust-v2.2.pdf) - Nordic APIs (PDF)
-* [Learning graphqL](https://riptutorial.com/Download/graphql.pdf) - Compiled from StackOverflow Documentation (PDF)
+* [Learning graphqL](https://riptutorial.com/Download/graphql.pdf) - Compiled from StackOverflow Documentation (PDF)  (CC BY-SA)
 
 
 #### Gremlin
@@ -867,7 +867,7 @@ Books on general-purpose programming that don't focus on a specific language are
 
 * [Building Java Projects with Gradle](http://spring.io/guides/gs/gradle/)
 * [Gradle Succinctly](https://www.syncfusion.com/ebooks/gradle_succinctly) - José Roberto Olivas Mendoza
-* [Gradle User Guide](https://docs.gradle.org/current/userguide/userguide.html) - Hans Dockter, Adam Murdoch ([PDF](https://docs.gradle.org/current/userguide/userguide.pdf))
+* [Gradle User Guide](https://docs.gradle.org/current/userguide/userguide.html) - Hans Dockter, Adam Murdoch ([PDF](https://docs.gradle.org/current/userguide/userguide.pdf)) (CC BY-NC-SA)
 
 
 #### Grails
@@ -893,7 +893,7 @@ Books on general-purpose programming that don't focus on a specific language are
 * [Cloudera Impala](https://docs.cloudera.com/documentation/enterprise/latest/PDF/cloudera-impala.pdf) - John Russel (PDF)
 * [Data-Intensive Text Processing with MapReduce](http://lintool.github.io/MapReduceAlgorithms/MapReduce-book-final.pdf) (Jimmy Lin and Chris Dyer) (PDF)
 * [Hadoop for Windows Succinctly](https://www.syncfusion.com/ebooks/hadoop-for-windows-succinctly) - Dave Vickers
-* [Hadoop Illuminated](http://hadoopilluminated.com/index.html) - Mark Kerzner, Sujee Maniyam
+* [Hadoop Illuminated](http://hadoopilluminated.com/index.html) - Mark Kerzner, Sujee Maniyam (CC BY-NC-SA)
 
 
 ### Haskell