#3791: remove last traces of bsddb.
diff --git a/Doc/library/shelve.rst b/Doc/library/shelve.rst
index 6dfef68..62005a4 100644
--- a/Doc/library/shelve.rst
+++ b/Doc/library/shelve.rst
@@ -102,12 +102,14 @@
.. class:: BsdDbShelf(dict[, protocol=None[, writeback=False]])
A subclass of :class:`Shelf` which exposes :meth:`first`, :meth:`next`,
- :meth:`previous`, :meth:`last` and :meth:`set_location` which are available in
- the :mod:`bsddb` module but not in other database modules. The *dict* object
- passed to the constructor must support those methods. This is generally
- accomplished by calling one of :func:`bsddb.hashopen`, :func:`bsddb.btopen` or
- :func:`bsddb.rnopen`. The optional *protocol* and *writeback* parameters have
- the same interpretation as for the :class:`Shelf` class.
+ :meth:`previous`, :meth:`last` and :meth:`set_location` which are available
+ in the third-party :mod:`bsddb` module from `pybsddb
+ <http://www.jcea.es/programacion/pybsddb.htm>`_ but not in other database
+ modules. The *dict* object passed to the constructor must support those
+ methods. This is generally accomplished by calling one of
+ :func:`bsddb.hashopen`, :func:`bsddb.btopen` or :func:`bsddb.rnopen`. The
+ optional *protocol* and *writeback* parameters have the same interpretation
+ as for the :class:`Shelf` class.
.. class:: DbfilenameShelf(filename[, flag='c'[, protocol=None[, writeback=False]]])