1. BONNIER, G, Selective fertilization in poultry, HEREDITAS 25: 65 (1939).
2. Die Gesetze der Vererbung uand Zuchtung 1938
3. CLARK, E, ANATOMICAL RECORD 101: 692 (1948).
4. CLARK, E., ANATOMICAL RECORD 105: 26 (1949).
5. CLARK E unpublished observation.