Only material that can be accessed should be cited. Personal communications by email or private message do not need to be listed in the References, only as an in-text citation.
(D. J. Matthews, personal communication, July 10, 2009)
Author, A. A. [@twittername]. (n.d.). Tweets [Twitter profile]. Retrieved Month Day, Year, from http://xxxxx
Tyson, N. G. [@neiltyson]. (n.d.). Tweets [Twitter profile]. Twitter. Retrieved October 8, 2019, from https://twitter.com/neiltyson
If you cite a particular post ('tweet'), you must cite it in the References page; you can follow the example and guidelines below.
Author, A. A.. [@twittername]. (Year, Month Day). Full text of tweet [Image attached/Thumbnail with link attached/etc] [Tweet]. Twitter. http://xxxxx
Obama, B. [@BarackObama]. (2009, July 15). Launched American Graduation Initiative to help additional 5 mill. Americans graduate college by 2020: http://bit.ly/gcTX7 [Tweet]. Twitter. http://twitter.com/BarackObama/status/2651151366
Author, A. A. [@username]. (Year, Month Day). Text of Caption [Photograph(s)/Video(s)]. Instagram. http://xxxxx
Tyree Library [@tyreelibrary]. (2018, October 12). Check out our spooky display for October! All of the books and movies on display are available for checkout [Photograph]. Instagram. https://www.instagram.com/p/Bo1uWOgAZ6b/