[ACE-OF-ACES]

what are the best sources?

For what ifs? Common sense.
Wiki is prone to biased interpretations.
If you like to query something at all, you cannot avoid reading printed books. Yes, trust me, there's some more knowledge than what you can find by google.
Possible starting points:
http://bit.ly/drfCMC
http://bit.ly/aeFUbh

Best regards - Mike

+1