Sheffield, C.S. et al (2008). «Diversity of cavity-nesting bees (Hymenoptera: Apoidea) within apple orchards and wild habitats in the Annapolis Valley, Nova Scotia, Canada.». Can. Entomol.140: 235-249. doi:10.4039/n07-058.
gutenberg.org
Fabre, Jean-Henri (1914). The Mason-Bees. New York: Dodd, Mead and Company.