diff --git a/books/free-programming-books-subjects.md b/books/free-programming-books-subjects.md
index ec8ab4f5d..f956d4049 100644
--- a/books/free-programming-books-subjects.md
+++ b/books/free-programming-books-subjects.md
@@ -2,6 +2,7 @@
 
 This list, organized by subject, is for books that cover a programming-related subject in a programming-language agnostic way.  
 Books that cover a specific programming language can be found in the  [BY PROGRAMMING LANGUAGE file](free-programming-books-langs.md) list.
+Books that cover a specific programming language can be found in the  [BY PROGRAMMING LANGUAGE](free-programming-books-langs.md) list.
 
 
 ### Index