These are some of the most helpful resources I know of:
David Briggs’ lecture on Traditional and Modern Colour Theory: https://www.youtube.com/watch?v=4enFjTGVTnc
James Gurney’s book “Color & Light” http://www.amazon.com/Color-Light-Guide-Realist-Painter/dp/0740797719
And several posts on his blog:
http://gurneyjourney.blogspot.com.es/2010/02/color-wheel-part-1.html
http://gurneyjourney.blogspot.com.es/2008/01/color-wheel-masking-part-1.html
“Alla Prima” by Richard Schmid:
http://www.richardschmid.com/Alla-Prima-II-By-Richard-Schmid-p/skuap.htm