MLA Style Guide, 8th Edition

• Use a brief parenthetical reference in your paper wherever you are incorporating someone else's words, thoughts, or ideas in your paper.
• In-text citations typically include the first element from the Works Cited entry (usually the first author's last name, but occasionally an abbreviated title) and a location (usually the page number).
• Each in-text or parenthetical citation should clearly correspond to a citation in the Works Cited list at the end of the paper.
• Identify the location of the information that you are citing as specifically as possible (page number, DVD disc number, video time, etc.).

• In-text references provide a means for you to give credit when using others' words, facts, or ideas. MLA style uses parenthetical notations to identify the source (author's surname) and the specific location (page reference) from which you borrowed material.  
• Place the parenthetical reference where a natural pause would occur, as near as possible to the material documented. In-text citations are typically placed at the end of a quote, sentence, or paragraph.
• You can provide the author's last name and page number at the end of the sentence enclosed in parenthesis, or the author's last name can appear as part of the sentence with the page number at the end of the sentence enclosed in parenthesis. If the author's last name was used in the sentence, do not repeat the author's name in the in-text citation.

Example:

According to B.F. Skinner, behavior analysis is necessary for society because "almost all major problems involve human behavior" (24).

- or -

Behavior analysis is necessary for society because "almost all major problems involve human behavior" (Skinner 24).

Work Cited

Skinner, B.F. Beyond Freedom and Dignity. Alfred A. Knopf, 1971, p. 24.