Since you do not identify the actual sources which you are using for your essay, this answer will define and illustrate how to format your sources in the MLA (Modern Language Association) format. A works cited must be double spaced and reverse indented (meaning the second line of each individual citation must be indented). 

If your source contains an author, and is found as part of an on-line site, the citation will look like this:

Last Name, First Name. "Name of Article," Name of Website. Publisher, publishing date. Web. Date of Access (Day Month Year). 

For example, I have accessed a random article on Beowulf and his heroic nature at the following site (http://historymedren.about.com/od/beowulf/p/beowulf.htm). The following is the correct MLA format for the article:

Snell, Melissa. "Beowulf: What You Need to Know About  the Epic Poem." About Medieval History. About.com, 2013. Web. 21 October 2013.

[NOTE: reverse indent missing from above citation because of incompatible formatting with this answer box word processor.]

When providing an in-text parenthetical citation for quoting, paraphrasing, or summarizing, one should use either the author or the article name. If an author is provided, then the last name of the author should appear in parenthesis following the borrowed text. For example, the article mentioned above states the following (used as a direct quote): "Beowulf is the oldest surviving epic poem in the English language and the earliest piece of vernacular European literature." To properly cite this in an essay, one would use the text and follow it with the last name of the author: 

"Beowulf is the oldest surviving epic poem in the English language and the earliest piece of vernacular European literature" (Snell). 

Be sure to use quotation marks when using a direct quote (word for word). If the author's name is not provided, one must use the name of the article. In this case, the in-text parenthetical citation would look like this: 

"Beowulf is the oldest surviving epic poem in the English language and the earliest piece of vernacular European literature" ("Beowulf: What You Need to Know About the Epic Poem"). 

Under normal circumstances, you will only need to use the first word or two off of the article title (in the case above, you would only need to place "Beowulf: What" in the parenthesis. You would only need to use more if you had similar title names. In this case, you would need to use just enough to differentiate between each of the articles. 

For example, if you had a title which was "Beowulf: What You Need to Know About the Epic Poem" and "Beowulf: What You Need to Know," you would use the complete title on the second article and up to "the" on the first. 

If you need further help on citing your articles, I have linked the OWL Purdue writing lab MLA citation site.This site is very extensive and helpful in defining citing procedures.