Online discussion list or discussion forum

Family name, INITIAL(S). Year. Title of message. Date added. Discussion group title. [Online]. [Date accessed]. Available from: URL

Example:

Stubbings, R. 2005. Diagnostic tests. 3 August. Lis-infoliteracy. [Online]. [Accessed 18 August 2017]. Available from: http://www.jiscmail.ac.uk