Added cross-references between the various archive file formats.
diff --git a/Doc/library/zlib.rst b/Doc/library/zlib.rst
index e57a156..edf5240 100644
--- a/Doc/library/zlib.rst
+++ b/Doc/library/zlib.rst
@@ -19,6 +19,10 @@
consult the zlib manual at http://www.zlib.net/manual.html for authoritative
information.
+For reading and writing ``.gz`` files see the :mod:`gzip` module. For
+other archive formats, see the :mod:`bz2`, :mod:`zipfile`, and
+:mod:`tarfile` modules.
+
The available exception and functions in this module are: