Write the speaker's last name, followed by a comma and her first name. Include an initial if she uses one for her middle name, and end with a period. MLA, APA and The Chicago Manual of Style all agree on this format. If there is more than one speaker, follow the citation rules for books: include the first speaker's last name, a comma and his first, and list subsequent speakers with their given names first.
Write the title of the lecture inside quotation marks and include a period inside the closing quotes. None of the three common style guides call for italicizing or underlining lecture titles. MLA citation rules specifically state that if there is no formal title to the lecture, simply put "Lecture" inside quotation marks.
Specify where the lecture took place. If it was in your class, include your course name and number. If it was a lecture at a convention, include the convention's title. End with a period and write the location, for example, the name of your university. Use another period after the location.
Write the city in which the lecture occurred, followed by a comma and the date. Formatting the date is the only place in which the three major styles diverge: MLA and APA both agree on formatting it as day-month-year, while Chicago calls for it to be formatted as month-day-year. APA allows for abbreviating the name of the month, but in MLA and Chicago, it should be spelled out in full.
Make sure that the final citation appears like these examples:
MLA: Lawrence, V. The Decline of the Mayan Culture. Archaeology 101: Intro to Archaeology. Angelo State University. San Angelo, 19 September 2013.
APA: Lawrence, V. The Decline of the Mayan Culture. Archaeology 101: Intro to Archaeology. Angelo State University. San Angelo, 19 Sept. 2013.
Chicago: Lawrence, V. The Decline of the Mayan Culture. Archaeology 101: Intro to Archaeology. Angelo State University. San Angelo, 19 September 2013.
Introduce the lecture in the text. In the body of your essay, the lecture should be identified in the text with an introductory statement like "During a lecture given on (date) by (speaker)..." before paraphrasing, or even quoting a portion of the lecture.