Harvard system is about reference citing. Some people want to learn the back story of it.
The system was original from an eminent zoologist Edward Laurens and a cytological scientist Mark. under mark’s influence, people from other industry started to write some words as footnote reference.
Mark conceived the citation and finally transferred it into common use.
Reference as a link shows the connection of the writer’s work with the original material they referenced to.
In-text citation and ent-text citation are the reference that the writer used in his text. Bibliography is a wilder list, for it covers all the book the writer engaged to.