diff --git a/glhr.cpp b/glhr.cpp
index d842861e..5fe827e7 100644
--- a/glhr.cpp
+++ b/glhr.cpp
@@ -229,8 +229,6 @@ EX void projection_multiply(const glmatrix& m) {
 
 EX void init();
 
-// https://www.opengl.org/sdk/docs/tutorials/ClockworkCoders/attributes.php
-
 #if HDR
 struct GLprogram : std::enable_shared_from_this<GLprogram> {
   GLuint _program;
diff --git a/shaders.cpp b/shaders.cpp
index b7f24445..1d5e5bae 100644
--- a/shaders.cpp
+++ b/shaders.cpp
@@ -28,6 +28,7 @@ constexpr flagtype SF_ZFOG         = 65536;
 
 #if HDR
 /* standard attribute bindings */
+/* taken from: https://www.opengl.org/sdk/docs/tutorials/ClockworkCoders/attributes.php */
 constexpr int aPosition = 0;
 constexpr int aColor = 3;
 constexpr int aTexture = 8;