N. M.  Williams and Thomson, J. D., ?Comparing pollinator quality of honey bees (Hymenoptera: Apidae) and native bees using pollen removal and deposition measures?, in For non-native crops, whence pollinators of the future?, K.  Strickler and Cane, J. H., Eds. Lanham, Maryland: Entomol. Soc. Amer., 2003, pp. 163 - 180.

J. H.  Cane, Minckley, R., Roulston, T., Kervin, L. J., and Williams, N. M., ?Complex responses within a desert bee guild (Hymenoptera: Apiformes) to urban habitat fragmentation?, Ecological Applications, vol. 16, pp. 632 - 644, 2006.