Here's an even better one for you:

[hmpf]

If I mention in a footnote that the author I'm writing about mentions, in one of *her* footnotes, that one detail of one panel of hers was vaguely inspired by the film "Heavy Metal", which in turn was inspired by a European comics anthology, and I mention that comic anthology's name, which is identical with the film's name, does that mean that I need to include info on both the original anthology and on the film in the list of Works Cited? (Incidentally, I know neither the film nor the anthology, myself, except in the sense that I have heard of them.)

And, as an encore:

If I mention that the name of the city most of Finder is set in is taken from the Narnia books of C.S. Lewis, do I need to dig up publication information on the Narnia books? I don't even own those... (I suppose I can look them up in the catalog of the British Library, though.)

I suspect the answer is 'yes' on all three...

*sigh*

Documenting sources. Hours of fun.