White Sapote —Julia Morton, Fruits of warm climates
Golden Berry, Passionfruit, and White Sapote: Potential Fruits for Cool Subtropical Areas—Richard McCain
Introduction and Domestication of Rare and Wild Fruit and Nut Trees for Desert Areas—Avinoam Nerd, James A. Aronson, and Yosef Mizrahi
New Crops as a Possible Solution for the Troubled Israeli Export Market—Y. Mizrahi and A. Nerd
Magness J.R. et al. 1971. Food and feed crops of the United States.
And outside links to more White Sapote info:
SAPOTE "FRUIT FACTS" (Fruit Facts are a series of publications of the the California Rare Fruit Growers, Inc. that contain information on individual fruits, including botanical identification, description and culture notes based on California research, and characteristics of cultivars).