http://buffy.wikia.com/wiki/Viewing_order_suggestion_for_Buffy_and_Angel
http://josswhedon.blogspot.com/2012/04/buffy-and-angel-episode-viewing-order.html?m=1
These are my favourite TV show episodes.
The optimal viewing order for episode of Buffy the Vampire Slayer and Angel, to keep the shows in chronological order as they crossover
http://slayalive.com/showthread.php/3924-The-Buffy-Angel-watching-guide
Buffyverse
by Robert Beardsley