Format: 

Author, A. A., & Author, B. B. (Date of lecture). Title of lecture [Lecture notes]. Retrieved from URL

In-text only: (A. Author, personal communication, Date of lecture)

Examples: 

Horowicz, K. & Nicosia, L. (2011, January 8). ARTstor: More than just art! [Lecture notes]. Retrieved from http://mycourses.rit.edu

In-text: (Horowicz & Nicosia, 2011)

Notes: 

Note: Lecture notes are not usually retrievable by others outside of the class so do not need to be included in the References list. Instead, include an in-text citation for personal communication and provide context within the body of the paper. If your professor requires that you cite class lecture notes posted to MyCourses or if the lecture notes are posted online outside of MyCourses, see the second example.

Source:
APA (ER) - p. 31