Color Harmony in Your Paintings by Margaret Kessler

A short work on picking and designing a color palette for your paintings. Covers using the Munsell color wheel, color temperature, receding colors and the like. A decent book on the subject but a trifle expensive on the used market.

The Urban Sketching Handbook: Working with Color: Techniques for Using Watercolor and Color Media on the Go by Shari Blaukopf

CYM palette