diff --git a/slicer/stl.c b/slicer/stl.c
index 074f6b1..7922715 100644
--- a/slicer/stl.c
+++ b/slicer/stl.c
@@ -10,6 +10,11 @@
  * (at your option) any later version.
  */
 
+/*
+ * Format description:
+ * http://en.wikipedia.org/wiki/STL_%28file_format%29
+ */
+
 
 #include <stdint.h>
 #include <stdlib.h>