https://extension.oregonstate.edu/master-melittologist
Bees of the Pacific Northwest : key to Lasioglossum species for females of the subgenera Hemihalictus, Sphecodogastra, and Evylaeus in Oregon (Hymenoptera : Halictidae)
Bees of the Pacific Northwest : key to bumble bee species for females (Hymenoptera : Apidae : Bombus)
Bees of the Pacific Northwest : key to genera (Hymenoptera : Anthophila)
Bees of the Pacific Northwest : key to bumble bee species for males (Hymenoptera : Apidae : Bombus)