When citing information from online lecture videos or notes, the sixth edition of the American Psychological Association (APA) style guide requires you to note the file format of the lecture materials you are referencing. The entry on your reference list will let your reader know whether you're drawing your information from a video, an online slideshow or notes in text form.
When citing an online lecture, use the following basic format: Author Last Name, First Initial(s). (Year). Title of lecture: Subtitles if applicable [file format]. Retrieved from URL.
For example: Cain, S. (2012). The power of introverts [video file]. Retrieved from http://www.ted.com/talks/susan_cain_the_power_of_introverts?language=en.
You can also use this format to cite notes or materials from a lecture that are found online. For example: Slingsby, S. (2013). RE Revision Notes [PowerPoint slides]. Retrieved from http://getrevising.co.uk/resources/re_powerpoint_for_unit_8.
Whenever you directly reference a lecture source in the body of your paper, include an in-text citation noting the source of the information. This should include the author of the lecture and the year. For example: (Cain, 2012) or (Slingsby, 2013).