Referencing is about maintaining academic integrity. It is used:
IN THE TEXT
In the Johann Gutenberg apprenticed as a goldsmith (Meggs 1998:69).
Cumming and Kaplan (1991:19) maintain that William Morris was seminal in founding the Arts and Crafts movement.
IN THE SOURCE LIST
Meggs, PB. 1998. A history of graphic design. Hoboken, NJ: John Wiley.