free cocompletion

Hi, the following result appears to be folklore: Given a locally small category C, the full subcategory of [C^op,Set] on small presheaves (i.e. those presheaves that are colimits of a small diagram of representables) is a free cocomplete locally small category on C. I've seen and heard this result in many places, and know how to prove it, but is there a proof written out in the literature? And where did the statement first appear? Paul -- Paul Blain Levy School of Computer Science, University of Birmingham http://www.cs.bham.ac.uk/~pbl [For admin and other information see: http://www.mta.ca/~cat-dist/ ]