1. Altieri, M. A., and L. C. Merrick. 1987. In Situ conservation of crop genetic resources through maintenance of traditional farming systems. Economic Botany 41:86–96.
2. Bellon, M. R. 1991. The ethnoecology of maize variety management: a case study from Mexico. Human Ecology 19:389–418.
3. Benz, B. F., L. R. Sanchez-Velasquez, and F. J. Santana Michel. 1990. Ecology and ethnobotany ofZea diploperennis: preliminary investigations. Maydica 35:85–98.
4. Bradfield, M. 1971. The Changing Pattern of Hopi Agriculture. Royal Anthropological Institute Occasional Paper No. 30. London: Royal Anthropological Institute of Great Britain and Ireland.
5. Breese, E. L. 1989. Regeneration and Multiplication of Germplasm Resources in Seed Genebanks: The scientific background. International Board for Plant Genetic Resources, Rome.