Abstract

References
1.
Chapis
N
. (1964 ) Amer. J. Obstet. Gynec.
90 , 272 .
2.
Johnston
G
Gordon
A
Rogers
H
. (1965 ) J. Obstet. Gynæc. Brit. Cwlth
72 , 292 .
3.
O'Leary
J
Bepko
F
. (1962 ) Obstet. and Gynec.
20 , 243 .
4.
Whelton
M
Sherlock
S
. (1968 ) Lancet
ii , 995 .
