MLA Handbook by 
The Chicago Manual of Style by 
Publication Manual of the American Psychological Association by There is no specific citation style that you are required to use in this course. You can use any one citation style.
Remember that the most important aspect of citation is consistency across your paper. Do not mix citation styles within a single research paper (for example, using MLA style in-text citations with Chicago style footnotes).
You should have learned the basics of citation from your academic writing courses and library workshops. Please refer to your past notes to refresh your memory, or check on the library books and websites on this topic. There are also many free resources that you can use to look up the various rules for citing in a specific style. This page will list some of them for your quick reference.
Other than the official manuals of the citation styles, you can also look at some quick guides online. These are created by universities around the world, and summarise the most commonly used rules for citation. If you cannot find the rule for a specific type of resource you wish to cite, to get in touch with NTU's Language and Communication Centre or the Library for a coaching session or research consultation respectively.