diff --git a/asciiWriter/wrap_single_line.py b/asciiWriter/wrap_single_line.py
index 8b69e42..ca947d1 100644
--- a/asciiWriter/wrap_single_line.py
+++ b/asciiWriter/wrap_single_line.py
@@ -1,3 +1,8 @@
+"""
+  Based on the textwrap2 module included in the PyHyphen library:
+  https://pypi.org/project/PyHyphen
+"""
+
 import textwrap
 
 class TextWrapper(textwrap.TextWrapper):