In your polished draft for your Op-Ed, which is due on November 9, you'll be asked to use in-text citations and create a works cited sheet for your sources.
Here is a link to MLA Guidelines from OWL at Purdue (the online writing workshop at Purdue University)
http://owl.english.purdue.edu/owl/resource/747/01/
If you scroll to the bottom, you'll see a numbered list of guidelines for how to create an in-text citation and how to create a works cited page.
Choose number 2 for the basics of in text citation.
Choose number 5 for the basics of a works cited page.
The entries that follow number five will tell you how to cite different kinds of texts on a works cited page.