There are many different citation styles used in academic papers. Some fields or professors have standard styles that they prefer. Regardless of the style you use, apply it consistently throughout your paper and make sure to proofread it the same way you would proofread the rest of your paper. Here are some guides with information on different citation styles.
Citation examples based on the References chapter from the 7th Edition of Scientific Style and Format (CSE 2006).
Raoult D, Audic S, Robert C, Abergel C, Renesto P, Ogata H, La Scola B, Suzan M, Claverie JM. 2004. The 1.2-megabase genome sequence of Mimivirus. Science. 306(5700):1344–1350.
(Raoult et al. 2004)
Pound P, Bracken MB. 2014. Is animal research sufficiently evidence based to be a cornerstone of biomedical research? BMJ [Internet]. [cited 2015 Jun 25]; 348:g3387. Available from http://www.bmj.com/content/348/bmj.g3387 doi: 10.1136/bmj.g3387
(Pound and Bracken 2014)
Johnson G. 2013. Don't ever whisper: Darlene Keju, Pacific health pioneer, champion for nuclear survivors. [Lexington (KY)]: [Giff Johnson].
de Silva K. 2009. Ka Mākālei a Kawainui. In: Kailua Historical Society. Kailua: in the wisps of the Malanai breeze. Kailua (Oʻahu): Kailua Historical Society. p. 50-53, 133-137, 161-165, 261-265.
(de Silva 2009)
Perez K 3rd. 2013. Ecological evaluation of coral reef resources at Kahaluʻu bay, Hawaiʻi. [dissertation]. [Honolulu]: University of Hawaiʻi at Mānoa.
[CSE] Council of Science Editors, Style Manual Committee. 2006. Scientific style and format: the CSE manual for authors, editors, and publishers. 7th ed. Reston (VA): Council of Science Editors. Chapter 29, References; p. 490-575.
Nānā i ke kumu
Citing the work that supports your research is both an ethical issue and a legal issue.
The ethics of citing is based on the scholarly tradition of giving credit for information and ideas that are not one's own. Science has a long tradition of acknowledging priority through citations. You have the ethical responsibility to cite all works that were used to support your research, to give credit to the earlier work and to provide a clear path for those who follow in your footsteps.
Or, to put it another way:
An example of some legal aspects of citing can be found in Copyrights, Title 17 of the U.S. Code, which describes the legal protections of authors' and creators' intellectual property rights within U.S. law.
*Pukui MK. 1983. ʻŌlelo Noʻeau : Hawaiian Proverbs & Poetical Sayings. Honolulu: Bishop Museum Press.  p.137.
Plagiarism is defined as:
"The action or practice of taking someone else's work, idea, etc., and passing it off as one's own; literary theft"
"plagiarism, n." OED Online. Oxford University Press, March 2015. Web. 21 May 2015. Available from: http://www.oed.com/view/Entry/144939
See the University of Hawaiʻi Student Conduct Code for more information.