How to cite e-mail?

[Patricia S. Bowne]

One of my students is writing a paper. She got
information over e-mail from a scientist with
IBM. She has his permission to quote from the
message in her paper, but how should she cite
it? I suggested using "personal communication"
in the body of the paper, but what about the
Literature Cited section? I don't remember ever
giving any citation for personal communications
in that section.

Pat Bowne