What's the best place to find a comic book character's bibliography?

Question

I'm looking for lists of every comic The Joker, the Mad Hatter, Mr. Sinister, & Mystique have been in. The Joker will be the most difficult, what with all the crossovers & everything. Anyone know where I can find a GOOD list of even one of them?

Answer 1

try wikipedia

Answer 2

Comicvine has most of them.  Not sure how complete or accurate the lists are, but that should get you started.