diff --git a/free-programming-books-de.md b/free-programming-books-de.md
index 68b711c2e923f86f2d5f7bb6a0f7e46ee5f598ff..519c9b883d449052ba7da2524edec7b8b6f9eb97 100644
--- a/free-programming-books-de.md
+++ b/free-programming-books-de.md
@@ -15,6 +15,7 @@
 * [LaTeX](#latex)
 * [Meta-Lists](#meta-lists)
 * [PHP](#php)
+* [PostgreSQL](#postgresql)
 * [Python](#python)
 * [Ruby on Rails](#ruby-on-rails)
 * [Scilab](#scilab)