Abstract

References
1.
Hartog
M
Gaafar
M A
Meisser
B
Fraser
R
. (1964 ) Brit. med. J.
ii , 1229 .
2.
Jackson
D
Grant
D B
Clayton
B
. (1968 ) Lancet
ii , 373 .
3.
Mattingly
D
. (1962 ) J. clin. Path.
15 , 374 .
