Personal communication, like interviews, letters, e-mails, phone calls, and in many cases lectures, can be handled in different ways. You can choose to cite these sources as you would any other type of source and include them in the reference list. If you do, it could be a good idea to list them under a separate heading ("In the author's possession" for example) to make it clear to the reader that it is unpublished material.
Since personal communication in many cases isn't available to the reader, it is commonly thought that this type of material shouldn't be in the reference list at all. Another way to handle personal communication is to only refer to the source in a footnote on the same page as the in-text citation. Please check with your supervisor, teacher or department what applies to you.
The reference should include information that clarifies the person’s real or made-up name, role, the form of communication and date.
Keep in mind that you need the relevant person’s permission before referencing your personal communication. You can also use anonymous informants. More information on rules of ethics for research is available at CODEX – a collection of rules and guidelines for research.