Because your readers do not have access to conversations, interviews, telephone calls, personal letters, and notes, APA style considers these and similar types of information "nonrecoverable data." Cite such information in the text, but do not include it in a list of references. List the initials and the last name of the person being used as a source, the type of communication, and the date of the communication.
A. P. French (personal communication, April 18, 1994)
(A. P. French , personal communication, April 18, 1994)