Add some internal links.
diff --git a/Doc/glossary.rst b/Doc/glossary.rst
index 4b0ab70..a051fe8 100644
--- a/Doc/glossary.rst
+++ b/Doc/glossary.rst
@@ -27,7 +27,7 @@
:ref:`2to3-reference`.
abstract base class
- Abstract Base Classes (abbreviated ABCs) complement :term:`duck-typing` by
+ :ref:`abstract-base-classes` complement :term:`duck-typing` by
providing a way to define interfaces when other techniques like
:func:`hasattr` would be clumsy. Python comes with many built-in ABCs for
data structures (in the :mod:`collections` module), numbers (in the
diff --git a/Doc/library/collections.rst b/Doc/library/collections.rst
index 3f81c00..bc3801a 100644
--- a/Doc/library/collections.rst
+++ b/Doc/library/collections.rst
@@ -28,7 +28,7 @@
===================== ====================================================================
In addition to the concrete container classes, the collections module provides
-ABCs (abstract base classes) that can be used to test whether a class provides a
+:ref:`abstract-base-classes` that can be used to test whether a class provides a
particular interface, for example, whether it is hashable or a mapping.
.. seealso::
@@ -959,6 +959,7 @@
subclass) or an arbitrary sequence which can be converted into a string using
the built-in :func:`str` function.
+.. _abstract-base-classes:
ABCs - abstract base classes
----------------------------