diff --git a/README.md b/README.md
index 27b11b1d6b6a0fafcf51fd0ca68f013997524362..ab151a9c7fae0e2504e4ea9dea81f881a2701a01 100644
--- a/README.md
+++ b/README.md
@@ -35,6 +35,7 @@ git submodule add https://github.com/glfw/glfw.git
 Optionals:
 
 ```
+git submodule add https://www.graphics.rwth-aachen.de:9000/ptrettner/ctracer.git
 git submodule add https://github.com/g-truc/glm.git
 git submodule add https://github.com/google/googletest.git
 git submodule add https://github.com/emil-e/rapidcheck.git