How do you cite an email?

According to The OWL at Purdue:

"Personal Communication: For interviews, letters, e-mails, and other person-to-person communication, cite the communicators name, the fact that it was personal communication, and the date of the communication. Do not include personal communication in the reference list.

(E. Robbins, personal communication, January 4, 2001).

A. P. Smith also claimed that many of her students had difficulties with APA style (personal communication, November 3, 2002).".