For information detailing how to reference personal communication Library's Page on Referencing Personal Communication. 

Please Note: As they do not provide recoverable data, personal communications are not included in the bibliography/works cited list.

Cite personal communications in text only. Give the initials as well as the surname of the communicator, and provide as exact a date as possible.

e.g. (J. Smith, personal communication, August 15, 2009)

e.g. J. Smith (personal communication, August 15, 2009) notes that...

e.g. The novelist has repeated this idea recently (Salman Rushdie, personal communication, May 1, 1995).