I haven't actually studied them directly, however David Weis...

I haven't actually studied them directly, however David Weis speaks well of them, and said his book was impressive.
David adopted and uses a hybrid version of the Darvas box style of support and resistance for his own trading, and seeing as I have adopted a lot of David's support and resistance and their placements, I guess I also use a similar style and placement as well.

cheers