referencing academic writing

When to reference
Academic writers need to support their arguments with evidence, and readers of academic writing need to evaluate the validity of that evidence. A reference is the bracketed or footnoted piece of information that tells the reader where the supporting evidence used in academic writing comes from. The role of the reference is twofold: firstly, it informs the reader of the source of your ideas so that he or she can distinguish between your words and ideas and those of others; secondly, accurate referencing and lists of references are necessary to allow the reader to evaluate the information and read further into the area.

Referencing is a system that allows you to acknowledge the contributions and work of others in your writing by citing your sources. A feature of academic writing is that it contains references to the words, information and ideas of others.
All academic essays MUST contain references. Referencing guards against plagiarism, a serious academic offence. Plagiarism is copying someone else’s words or ideas and presenting them as your own.

A great resource for how to cite in different styles, including useful example papers. Covers APA (social sciences), Chicago/Turabian (history) and MLA (humanities) as well as CBE (hard sciences).
If you are in any doubt about the tecnicalities of avoiding accusations of plagiarism, even unintentional, do this tutorial!

References:

http://student.unsw.edu.au/referencing-essay
http://caw.ceu.edu/citation-styles-using-sources
http://headstartacademicenglish.com/2019/04/18/the-importance-of-referencing-in-academic-writing/