1. Brown, E. 1970. Guide to the identification of potato varieties. National Institute of Agricultural Botany, Cambridge.
2. —. 1973. Preliminary survey on the identification of potato varieties by tuber characters. J. Natn. Inst. Agric. Bot. 13:67–86.
3. Crow, J. F., and M. Kimura. 1970. Introduction to population genetics theory. Harper & Row, New York.
4. Fisher, R. A. 1946. Statistical methods for research workers. Oliver & Boyd, Edinburgh.
5. Hall, A. V. 1970. A computer based system for forming identification keys. Taxon. (1970) 19:12–18.