Sheffield, C.S., Ratti, C., Packer, L., Griswold, T. 2011. Leafcutter and Mason Bees of the Genus Megachilidae Latreille (Hymenoptera: Megachilidae) in Canada and Alaska. Canadian Journal of Arthropod Identification No. 18, 29 November 2011, available online at http://www.biology.ualberta.ca/bsc/ejournal/srpg_18/srpg_18.html, doi: 10.3752/cjai.2011.18