Harvard Style Guide: Citing same author, multiple works, same year

To cite multiple works by the same author in the same year, use lower-case letters after the publication date in your in-text citations. This applies to any type of source including books, journal articles, tweets etc.

In-Text-Citation: 

Research has focused on whether high-density housing, in city centres, is one answer to mitigate against homelessness (Wilmot 2020a; 2020b).

Wilmot (2020a) conducted intense research work with community organisations on homelessness. She came to the conclusion that high-density, city centre housing was not the answer (Wilmot 2020b).
 

Example: 

Wilmot M. (2020a) Inclusion: When will we have a Home for Life? Dublin: Pearson.

Wilmot M. (2020b) Solutions and Barriers to Homelessness. Dublin: Pearson.

Still unsure what in-text citation and referencing mean? Check here. 

Still unsure why you need to reference all this information? Check here.