In Harvard Style, Referencing is a two-part process : Citation in the text and Reference list / Bibliography.
Citation in the text is the brief indication of source within the text of your work immediately following the use of the source whether quoted or summarised.
Reference list / Bibliography are listed at the end of the work and are organised alphabetically by the surname of the author.
A reference list includes all works that have been cited or referred to in the assignment.
A bibliography includes all the material consulted when writing the assignment even if it is not been directly cited/referenced in the assignment.
[The term referencing and bibliography can be used interchangeably at some places]