1. Ackery, P. R., and Vane-Wright, R. I., Milkweed butterflies: their cladistics and biology. British Museum (Natural History), Comstock Publishing Associates, Cornell University Press, Ithaca, New York 1984.
2. Anderson, J. A., and Brower, L. P., The cold-hardiness of the monarch butterfly during its annual cycle of overwintering, migration and breeding, in: Biology and Conservation of the Monarch Butterfly. Eds. S. B. Malcolm and M. P. Zalucki. Natural History Museum of Los Angeles County, Contributions in Science, Los Angeles, in press 1989.
3. Borkin, S. S., Notes on the shifting distribution patterns and survival of immatureDanaus plexippus (Lepidoptera: Danaidae) on the foodplantAsclepias syriaca. Great Lakes Ent.15 (1982) 199–206.
4. Brower, L. P., Brower, J. V. Z., and Corvino, J. M., Plant poisons in a terrestrial food chain. Proc. natl Acad. Sci.57 (1967) 893–898.
5. Brower, L. P., Ryerson, W. N., Coppinger, L. L., and Glazier, S. C., Ecological chemistry and the palatability spectrum. Science161 (1968) 1349–1351.