How do I reference a lecture both in text and on the reference page. Also, would an 'an' be used befor the abbreviations LPN and RN?

Question

For question 1, according to MLA, reference a lecture as follows:

Speaker's Last name, First name and Initial. "Title of the presentation (if known)." The meeting title (if given). The sponsoring organization (if given). Location. Day, Month, Year.

example:

Atwood, Margaret. "Silencing the Scream." Boundaries of the Imagination Forum. MLA Convention. Royal York Hotel, Toronto. 29 Dec. 1993.

For question 2, the answer is "yes".

Thank you!