1. Bartlett, M. S., J. R. Statist. Soc., Supp., 3, 185 (1936).
2. Beall, G., Biometrika, 30, 422 (1939).
3. Beall, G., Biometrika, 32, 243 (1942).
4. Bliss, C. I., Proc. Tenth Int. Congr. Entom., 1956, 2, 1015 (1958).
5. Bliss, C. I., and Owen, A. R. G., Biometrika, 45, 37 (1958).