R. M.  Duffield, LaBerge, W. E., Cane, J. H., and Wheeler, J. W., ?Exocrine secretions of bees. IV. Macrocyclic lactones and isopentenyl esters in Dufour?s gland secretions of Nomia bees (Hymenoptera: Halictidae)?, vol. 8, pp. 535 - 543, 1982.

J. H.  Cane, ?Pollinating bees (Hymenoptera: Apiformes) of U.S. alfalfa compared for rates of pod and seed set?, Journal of Economic Entomology, vol. 95, pp. 22 - 27, 2002.