Abstract

References
1.
Becker
W B
Uys
C J
. (1967 ) J. comp. Path . 77 , 159
2.
Pereira
H G
Tumova
B
Law
V G
. (1965 ) Bull. Wld tilth Org . 32 , 855
3.
Pereira
H G
Tumova
B
Webster
R G
. (1967 ) Nature (Lond.)
215 , 982
4.
Stubbs
E L
. (1959 ) In: Diseases of Poultry . Ed.
Biester
H E
De Vries
L
. 4th ed. Ames, Iowa; p 599
