diff --git a/src/iota/crypto/__init__.py b/src/iota/crypto/__init__.py
index <HASH>..<HASH> 100644
--- a/src/iota/crypto/__init__.py
+++ b/src/iota/crypto/__init__.py
@@ -6,6 +6,7 @@ from __future__ import absolute_import, division, print_function, \
 # Load curl library.
 # If a compiled c extension is available, we will prefer to load that;
 # otherwise fall back to pure-Python implementation.
+# https://pypi.python.org/pypi/PyOTA-CCurl
 try:
   from ccurl import *
 except ImportError:
Added reference link for PyOTA-CCurl.