E-mails, instant messages, unpublished personal interviews, conversations, unrecorded lectures, and any other communication that is not available publicly should be cited as a Personal Communication. Personal Communications only require an in-text citation. They do not need an entry on the References page.
In-text Citation Format:
... (A. A. Author, Personal communication, Month Day, Year).
...(D. Hoiland, Personal communication, December 5, 2022).