Rightmyer, M. G., Kono, Y., Kohn, J. R., & Hung, K.-L. J. (2014).

A new species of Triepeolus (Hymenoptera: Apidae), with comments on
T. utahensis (Cockerell) and T. melanarius Rightmyer

. Zootaxa, 3872(1), 48–56. https://doi.org/10.11646/zootaxa.3872.1.4