Abstract

References
1.
Formston
C
Knight
G C
. (1942 ) Vet. Rec.
46 , 481
2.
Frost
C
. (1959 ) Vet. Rec.
71 , 687
3.
Stephens
F E
Kerby
J P
. (1946 ) J. Hered.
37 , 153
