Add links to helpful external resources.
diff --git a/Doc/library/functions.rst b/Doc/library/functions.rst
index 9de9db6..3789e20 100644
--- a/Doc/library/functions.rst
+++ b/Doc/library/functions.rst
@@ -1104,10 +1104,12 @@
*reverse* is a boolean value. If set to ``True``, then the list elements are
sorted as if each comparison were reversed.
- In general, the *key* and *reverse* conversion processes are much faster than
- specifying an equivalent *cmp* function. This is because *cmp* is called
- multiple times for each list element while *key* and *reverse* touch each
- element only once.
+ In general, the *key* and *reverse* conversion processes are much faster
+ than specifying an equivalent *cmp* function. This is because *cmp* is
+ called multiple times for each list element while *key* and *reverse* touch
+ each element only once. To convert an old-style *cmp* function to a *key*
+ function, see the `CmpToKey recipe in the ASPN cookbook
+ <http://code.activestate.com/recipes/576653/>`_\.
.. versionadded:: 2.4
diff --git a/Doc/library/math.rst b/Doc/library/math.rst
index 4ecd14e..4d566a5 100644
--- a/Doc/library/math.rst
+++ b/Doc/library/math.rst
@@ -100,6 +100,10 @@
occasionally double-round an intermediate sum causing it to be off in its
least significant bit.
+ For further discussion and two alternative approaches, see the `ASPN cookbook
+ recipes for accurate floating point summation
+ <http://code.activestate.com/recipes/393090/>`_\.
+
.. versionadded:: 2.6