add some documentation for 2to3
diff --git a/Doc/glossary.rst b/Doc/glossary.rst
index 81e29f1..2655327 100644
--- a/Doc/glossary.rst
+++ b/Doc/glossary.rst
@@ -22,7 +22,8 @@
source and traversing the parse tree.
2to3 is available in the standard library as :mod:`lib2to3`; a standalone
- entry point is provided as :file:`Tools/scripts/2to3`.
+ entry point is provided as :file:`Tools/scripts/2to3`. See
+ :ref:`2to3-reference`.
abstract base class
Abstract Base Classes (abbreviated ABCs) complement :term:`duck-typing` by