If you are interested in showing Koi, or understanding Koi breeding for color, this book has many insights into Koi genetics, and how color traits are inherited.
The book is entitled: Inheritance of colors and evolution of Koi and carp: A study about genetic diversity of carp populations, inheritance of color traits in koi and evolution of the tetraploid genome of this species. It is 108 pages.
WARNING. Review by Spike Cover: "It's likely not worthwhile for hobbyists, and is difficult to understand."