Personal communication in the text of your document must include:
It is recommended you get permission from the source/author of your personal communication.
In a conversation with a A. B. Smith, MD (April 2010)...
According to a letter by C. D. Jones (Assoc. Prof., Dept of Philosophy, University of Pittsburgh, PA, unreferenced) in November 2010...
According to C.D. Jones , PhD (written communication, November 2010)...
In‐text: In an email from E. Ferguson, PhD (email@example.com) in August 2010...
It is important to keep a copy of the email.
Reference list for archived personal communication:
Author Last Name, First Name (Author Affiliation). Letter (Email, Telegram, etc.) to: Recipient (Recipient Affiliation). YYYY MMM DD ([cited YYYY MMM DD] if needed). Pagination. Located at: Library, City, State/Country; Box number, Folder number. Language other than English or Note (if available). OR Available from: URL
Kerr, J. Auston (Chevy Chase, MD). Letter to: Ramon Cordoba Palacio (Medellin, Colombia). 1974 Nov 11. 11 p. Located at: Modern Manuscripts Collection, History of Medicine Division, National Library of Medicine, Bethesda, MD; MS C 456.
Hennen, John (Edinburgh, Scotland). Letter to: Dr. Duncan. [date unknown]. 9 p. Located at: History of Medicine Division, National Library of Medicine, Bethesda, MD; W6 P3 v.1575. Observations on the cure of syphilis without mercury.
Michaels, Kristin (Society of Hospital Pharmacists of Australia, Collingwood, AU). Letter to: Kate Thomann (Department of Health, Canberra, AU). 2019 Jul 17 [cited 2021 Sep 16]. 5 p. Available from: https://www.shpa.org.au/sites/default/files/uploaded-content/website-content/Submissions/shpa_submission_to_doh_-_review_of_pip_ihi.pdf
Pina, Luciano (Santiago, Chile). Letter to: D.M. Arroyo de Veracruz ([Mexico]). 1845 Jun 26. 4 leaves. Located at: Modern Manuscripts Collection, History of Medicine Division, National Library of Medicine, Bethesda, MD; MS F 196. Spanish.
Source for reference list:
Patrias K. Citing medicine: the NLM style guide for authors, editors, and publishers [Internet]. 2nd ed. Wendling DL, technical editor. Bethesda (MD): National Library of Medicine (US); 2007 [updated 2009 Oct 21; cited 2019 Jan 8]. Available from: http://www.nlm.nih.gov/citingmedicine