Classic and helpful papers

​Jander 1976 - Grooming and pollen manipulation in bees.pdf

Michener 1953 - The biology of a leafcutter bee (Megachile brevis) and its associates.pdf

​Michener 1979 - Biogeography of the bees 

​Michener et al. 1994 - The bee genera of North and Central America.pdf

​Mitchells Bee's of the Eastern US (split into multiple PDFs): [Introduction] [Andrenidae] [Apidae - Apis and Bombus] [Apidae - Anthophoridae] [Colletidae] [Halictidae] [Megachilidae] [Mellitidae]