Identifying the source in your text is essential for every kind of borrowing of information excepting common knowledge.
The first element in an in-text citation is usually the first element in a works cited entry which is usually the author's name followed by a page number.
Author
If the works cited list has two authors, include both last names in the in-text citation followed by the page number.
(Doris and Erdirch 23).
If the sources has 3 or more authors, the in-text citation will have et al. after the first author's last name followed by the page number
(Burdick et al. 42)
If the author's name is used in the sentence, only include page number within parenthesis.
According to Burdick, ... (42)
For corporate author, abbreviate terms that are commonly abbreviated (Dept.).
Separate administrative units by commas (United States, Dept. of Labor 147)
Page Number
The page number is within parenthesis and is placed, when possible, where there is a natural pause in the text. Use same style of numeral as the source.
According to Naomi Baron, reading is "just half of literacy. The other half is writing" (194).
Quotation
A parenthetical citation that follows a quotation is directly placed after the closing quotation mark. The author's name may appear in the text itself or, abbreviated, before the page number in the parenthesis.
Reading is "just half of literacy. The other half is writing" (Baron 194).
Title
If an entry begins with the title, the in-text citation contains the title. The title may appear in the text itself or abbreviated before the page number in the parenthesis. The abbreviated title should begin with the word by which the title is alphabetized. Omit initial article.
"The Double Vision: Language and Meaning in Religion" can be abbreviated as "Double Vision".
If the title does not begin with a noun phrase, cite the first word if it is enough to direct the reader to the correct entry.
"And Quiet Flows the Don" may be abbreviated to "And".
Multivolume Work
(Webster, vol. 4)
Video and audio recordings
Include the time or range of times. Give the hours, minutes and seconds as indicated by the media player you use separating the numbers with colons. ("Buffy" 00:03:16-17).
If the source uses paragraph numbers rather than page numbers (some web sources may not contain page numbers), give the relevant number or numbers preceded by par or pars.If a source does not have page numbers or other numbers, there is no need to count the paragraphs or pages.
Repeated Use of Sources
If you borrow more than once from the same source within a paragraph, and no other source intervenes, you can use a single parenthesis after the last borrowing.
(Zender 138, 141)
If you break up the borrowing into parts and include material from another source, you should repeat the author's name in the second citation.
You can also define a source at the beginning of the text as follows:
According to Karl F, Zender, Romeo and Juliet presents..."first quote" (131)..."second quote" (141).
Punctuation
Citations of multiple sources in a single parenthesis are separated by semicolons.
(Baron 194; Jacobs 55)
Citations of different locations in a single source are separated by commas.
(Baron 194, 200, 197-198)
Additional information related to in-text citations can be found in section 3 (pp. 116-128) of The MLA Handbook. Also check Purdue's OWL page