Information in your research paper should come from a reliable source in order to lend credibility to your ideas. PhD theses and dissertations may sometimes fulfill that requirement, particularly since they stem from academic institutions. After determining that a thesis or dissertation makes an appropriate source, follow the guidelines to cite the piece properly.
According to the MLA Handbook for Writers of Research Papers (7th Edition), the parenthetical citation for a thesis or dissertation includes the author's last name and a page number. On the Works Cited page, an unpublished piece begins with the author's name, last name first. Then type the title of the paper, in quotation marks. Type "Diss." (without the quotation marks) to indicate it is a dissertation or thesis followed by the city of publication and the year. Then list the publication medium, such as Print. Put a period between all portions except between the city and year, where you should use a comma. For those published on the Internet, use Web as the medium and follow that with the date you accessed the page.
As the Publication Manual of the American Psychological Association (6th Edition) indicates, in-text citations for such papers in an APA essay include the author's last name and the publication date, just like other types of sources. On the References page, give the author's first, last name followed by initial. After a period, put the publication date in parentheses with a period at the end. Type the title of the dissertation or thesis, italicized followed by "Doctoral dissertation" or "Unpublished master's thesis," whichever is the appropriate language, in parentheses (without the quotation marks). Type the name of the institution, a comma and the location of that institution or "Retrieved from" (without the quotation marks) and the URL for those taken from an online database.