1. Cersovsky, H., Tierzucht, 11, 185 (1957).
2. Maymone, B., and Molossini, F., Ann. Sper. Agric., 13, 1005 (1959).
3. Blau, G., Zuchtungskunde, 33, 380 (1961).
4. Gerdemann, H., Dissert. Univ. Hanover (1964).
5. Milk Marketing Board, Prod. Div. Rep., 11, 78 (1961).