and offers an excellent introduction section which delves into the topic of
metaclass compatibility.
-L<http://www.iam.unibe.ch/~scg/Archive/Papers/Duca05ySafeMetaclassTrait.pdf>
+L<http://scg.unibe.ch/archive/papers/Duca05ySafeMetaclassTrait.pdf>
=item "Safe Metaclass Programming"