Information you use for your write ups must credit where that info comes from, even if it is not formally published, and could include your notes from a lecture or a personal email or letter. A typical lecture/lecturer's handouts or slides are a bit different and can be cited much like other material.
APA Style
Emails or Your Lecture Notes
Either of these are considered a "personal communication" simply because it is not public or "recoverable" data. It is simply referenced in the text of the document and does not have any entry in the bibliography.
Lecturer Slides or Handouts
Can be cited like other items (books or journals), so in the text, use author & date. In the bibliography, Include 5 pieces of information:
- Author (in other words, the lecturer)
- Date
- Title
- Brackets with description (i.e., [powerpoint slides])
- Organization (e.g., city, & country : university, department)
To see what that looks like, check the list of examples.
