This system is usually adopted by psychology and related disciplines. Here at the University of Hull it is the recommended referencing system for students studying Psychology; Sports, Health and Exercise Science; and some other subject areas.
The APA style is about more than just referencing, it also involves how you format documents. It is similar to the author-date system, but with minor differences and is sometimes called Harvard APA. The APA referencing style is periodically updated. The current style is also known as APA 6th.
Your tutors may give you alternative guidelines.
The official APA style manual is not available for free but can be bought from all good booksellers for £20-£25 (Kindle edition slightly less).
Although the punctuation and order of information may be slightly different, you may still find our UoH Harvard Guidelines useful for checking what information you should be including when citing more unusual sources.