U.S. Department of Agriculture, Technical Bulliten
Thirteen new species of halictid bees in the genus Dufourea are described. Also described are females of two species known previously only from males. All are from the Western United States and northern Mexico.
Bohart, George E., "New Species of North American Bees of the Genus Dufourea (Hymenoptera, Halictidae) with Descriptions of Two Previously Undescribed Females" (1980). All PIRU Publications. Paper 789.