Referencing:

In all academic work you need to acknowledge the sources on which you have drawn. This not only allows readers to locate and follow up the original source for themselves (as you may do in identifying sources for your review), but lends support and weight to your arguments and the discussion of the topic. You are demonstrating familiarity with the literature and an ability to use it to elucidate the field of study and support your particular approach.

It is essential, then, that you provide appropriate references both within the text and, in the form of a bibliography, at the end.