Here's a research tip that I live by [what, did you guys think I kept all this info in my head?]:
At
Psyche Buffy Transcripts you can download PDF files of an entire season's transcripts. Just download 1 - 5 and then you can search for relevant terms, like dream, sleep or wake.
That's how I compiled the lore of Joss with regard to demons, that I posted several weeks ago.
That's also why I like to remind people not to cheat with "Who Said That?" quotes, because it would just be an easy look-up that way.