Proshchalykin, M. Y., & Kuhlmann, M. (2012). The bees of the genus Colletes Latreille 1802 of the Ukraine, with a key to species (Hymenoptera: Apoidea: Colletidae). Zootaxa, 3488(1), 1–40. https://doi.org/10.11646/zootaxa.3488.1.1