diff --git a/thanks.md b/thanks.md
index bb4d48c17612cedebeecae9a8c9c5c651866feeb..4f65b5d21da4dd42746de529b2f2e0103a140140 100644
--- a/thanks.md
+++ b/thanks.md
@@ -1,6 +1,9 @@
 ### References
 
-[1]: **Git** Book: https://git-scm.com/book/en/v2
+[1]: **Git** Book:
+https://git-scm.com/book/en/v2
+
+<br>[2]: GitHub training services: https://services.github.com/training/
 
 
 ### Cheat sheet