We thought we would pass on that advice and elaborate on it slightly.
How do you cite a message from beyond the grave?
Well, that depends on whether the spirit spoke to you directly or if its words were written down by a human agent.
If you have a book, pamphlet or other piece of text that was written "by" a spirit, but dictated to a human, then you have to cite the human agent as the author. The APA blog recommends citing the human agent as the only author, but you may include the spirit as well, if the publication details of the book (or what have you) includes the spirit as part of the official bibliographic details.
So, for example, the novels written by the ghost of Patience Worth, as dictated to Pearl Curran, could be cited as though Curran was the author, or it could be cited as though both were authors:
Curran, P. (1917). The sorry tale: A story of the time of Christ. New York, NY: Holt.
Worth, P. [Spirit], & Curran, P. (1917). The sorry tale: A story of the time of Christ. New York, NY: Holt.In text you would have: (Curran, 1917) or (Worth & Curran, 1917).
If the spirit communicated to you personally, you would just treat it like personal communication. For APA, this means you would only cite it in text, and you would not include it in your reference list: (A. C. Doyle [Spirit], personal communication, April 1, 2014).
If the spirit spoke via a medium, it would be best to cite the medium in this case: (M. Crandon [Medium], personal communication, April 1, 2014).
Why would you cite a message from beyond the grave?
This is probably a more important question to answer, before you go citing spirits in your assignments.
If you were writing a paper about spiritualism, attitudes towards spiritualism or works supposedly written by spirits, then citing a book "written" by a spirit would be perfectly legitimate.
If, however, you were writing about rotator cuff injuries in athletes (for example) - or any other topic where spirits are not normally considered to be reputable sources of information by the academic community - then you should restrict your sources to people who were alive at the time of writing.
And while citing "personal communication" delivered via a medium may also be relevant if you were researching spiritualism, it would be best if you always made it clear that the medium was your source of information, rather than citing the spirit directly.
If the spirit communicated with you directly, you probably shouldn't use that information in your assignment as most incorporeal sources are considered unreliable.