<a href="http://www.cs.berkeley.edu/~lorch/personal/self-ref.html" rel="nofollow">http://www.cs.berkeley.edu/~lorch/personal/self-ref.html</a> an actually attributed and correct version<p><a href="http://www.chaos.org.uk/~eddy/craft/srat-Q.html" rel="nofollow">http://www.chaos.org.uk/~eddy/craft/srat-Q.html</a> this one is the same, but lets you bookkeep