What you need to be aware is for any online notes, make sure that you provide the format of the file in brackets after the lecture title as provided below
Ahmad, M.A.N. Archery is good for mental health [PDF document]. Retrieved from Lecture Notes Online Web site: http://www.azminias.com/archery_health.htm
If anyone is writing a thesis or any scientific writing which is not going to be peer-reviewed blindly, in that case you can possibly (!) use PPs, however it's recommendable not to use PPTs. PPTs are unpublished works, so, for scientific articles, most of the journals do not encourage to insert unpublished works. Even sometimes, web links are not encouraged to insert.