Reference to the unpublished lecture notes
In APA (6th) citation style, it would look like this:

Kanazawa, M. (2012). Context-free tree grammars. Lecture, Place/University. Retrieved 4 May 2017, from https://pdfs.semanticscholar.org/95a3/cb63b80c3416879d534f41eedcd174b40159.pdf

The Place/University should be corrected. Could be SemanticScholar.

Nevertheless, I'd check (before citing this lecture note) whether the information you want to cite is included in one of the given references.

Note: Since the desired citation style is not clear, I used APA as default. I can change the citation style, if the desired one is added to the question.