So who owns the idea of "In Box Zero"?

I know that David Allen is the originator of much of this (I’ve read the GTD bible a few times) but Kelly Forrister recently claimed that the ‘in box zero’ idea was all David Allen’s during a podcast: http://www.davidco.com/podcasts/play/15.html

I’m confused since I read about ideas leading up to ‘in box zero’ here a while ago and recently viewed our illustrious editor’s Google presentation on the topic.

In the new world of Web 2.0, is citation of sources no longer needed? I know Wittgenstein claimed that ‘no ideas are new’ and that Bob Dylan once said, “if there’s an original thought out there, I could use it right now” (Brownsville Girl) but tipping ones hat to the pantheon of co-creating mashers seems a good idea to me still. http://theanthrogeek.wordpress.com/