There are no guidelines regarding nonrecoverable material. The Library recommends following the guidelines for personal communication.
Personal communication is cited in text only (as personal communications cannot be retrieved by the reader, you should not include them in the reference list).
Author-Date style
Format:
(Originator of the communication, medium, Day Month, Year)
Example:
(OpenAI’s ChatGPT, response to question from author, 30 March, 2023)
Notes and Bibliography style
Format:
Number Originator of the communication, medium, Day Month, Year.
Example:
1 OpenAI’s ChatGPT, response to question from author, 30 March, 2023.