Abstract

Get full access to this article
View all access options for this article.
References
1.
Jackson
R. C.
Woodruff
A. W.
(1963 ) Brit. med. J.
1 , 1367 .
2.
Smitskamp
H.
Wolthuis
F. H.
(1971 ), Brit. med. J. , 1 , 714 .
3.
Woodruff
A. W.
Dickinson
C. J.
(1968 ), Brit. med. J. , 3 , 31 .
