Adding a link to the docs

docs/index.txt

@@ -259,6 +259,7 @@ References
 
 Articles and blog entries on testing with Mock:
 
+* `Checking multiple calls with mock and coping with mutable arguments <http://www.voidspace.org.uk/python/weblog/arch_d7_2010_11_20.shtml#e1197>`_
 * `Mocking unbound methods and properties <http://www.voidspace.org.uk/python/weblog/arch_d7_2010_11_20.shtml#e1196>`_
 * `Mocking patterns: chained calls, partial mocking and open as context manager <http://www.voidspace.org.uk/python/weblog/arch_d7_2010_10_02.shtml#e1188>`_
 * `Mock recipes <http://konryd.blogspot.com/2010/06/mock-recipies.html>`_