lucy24 - 12:32 am on May 28, 2012 (gmt 0)
There's always the Columbo approach.
"Hey, professor, musta been a coupla years since we talked. I'm the author of pages such-and-such. I've misplaced the e-mails where we talked about permissions, and my bookkeeper is getting cranky. Can you re-send me what you've got?"