C. S.  Sheffield and Westby, S. M., ?The male of Megachile nivalis Friese, with an updated key to members of the subgenus Megachile s. str. (Hymenoptera : Megachilidae) in North America?, JOURNAL OF HYMENOPTERA RESEARCH, vol. 16, pp. 178-191, 2007.

C. S.  Sheffield, Kevan, P. G., Westby, S. M., and Smith, R. F., ?Diversity of cavity-nesting bees (Hymenoptera : Apoidea) within apple orchards and wild habitats in the Annapolis Valley, Nova Scotia, Canada?, CANADIAN ENTOMOLOGIST, vol. 140, pp. 235-249, 2007.