There are a number of referencing styles. They are discipline-specific and, in some circumstances, depend on the type of document you are writing:
Re:Cite is an interactive library website that provides introductory information for a limited number of styles and reference types: APA 6th, Harvard, Chicago, MLA, Vancouver and AGLC.
More detailed information can be found in a style manual or guide, including those listed below:
APA (American Psychological Association)
MLA (Modern Language Association of America)
AGLC (Australian Guide to Legal Citation)
Other styles and guides