Personal communications, such as private letters, personal emails, phone conversations, and personal interviews, are one of the few source types that are only cited in the text of your paper, and not on your Reference Page. According to the APA Manual (2010), "Because they do not provide recoverable data, personal communications are not included in the reference list. Cite personal communications in text only" (p. 179).
In order to cite a personal communication in text, give the initials and last name of the communicator (e.g. the person you interviewed, spoke to on the phone, etc.), and the date of your communication with them:
J. Smith (personal communication, May 5, 2014)
(B.V. Williams, personal communication, September 22, 2013)