Any good topology sites?

I’ve been enjoying making models but I often struggle to get the topology right. Figuring out how to keep good flows in it, avoid triangles and use squares mostly etc, but I can’t find anything too good on general topology. It seems to just focus on faces etc.

Does anyone know any good sites, books or dvds to aid in this that they could recommend?

poly_regions.jpg and polycount are great places to learn.