Abstract

References
1.
Barnicot
N A
Wolffson
D
. (1952 ) Lancet
i , 893 .
2.
Brink
A J
. (1951 ) S. Afr. J. clin. Sci.
2 , 288 .
3.
Goldman
M H
. (1960 ) Amer. Heart J.
59 , 71 .
4.
Grusin
H
. (1954 ) Circulation
9 , 860 .
5.
Littman
D
. (1946 ) Amer. Heart J.
32 , 370 .
6.
Powell
S J
. (1959 ) Brit. Heart J.
21 , 263 .
7.
Wasserburger
R H
. (1955 ) Amer. J. med.
18 , 428 .
