diff --git a/_licenses/gfdl-1.3.txt b/_licenses/gfdl-1.3.txt
index 7177c40..4967ab2 100644
--- a/_licenses/gfdl-1.3.txt
+++ b/_licenses/gfdl-1.3.txt
@@ -10,7 +10,10 @@ how: Create a text file (typically named COPYING, as per GNU conventions) in the
 note: The Free Software Foundation recommends taking the additional step of adding a boilerplate notice after the title of a licensed document. The boilerplate can be found at the "addendum" part of the license.
 
 using:
-
+  GNU LilyPond (Documentation): https://git.savannah.gnu.org/cgit/lilypond.git/tree/COPYING.FDL
+  GNU nano (Documentation): https://git.savannah.gnu.org/cgit/nano.git/tree/COPYING.DOC
+  GNU Scientific Library (Documentation): https://git.savannah.gnu.org/cgit/gsl.git/tree/doc/_static/fdl.txt
+  
 permissions:
   - commercial-use
   - modifications