Abstract

References
1.
Butler
N R
. (1973 ) In: Elliott & Knight (1973) , p 151 .
2.
Elliott
K M
Knight
J
. ed (1973 ) Ciba Foundation Symposium 10 (new series) . Excerpta Medica , Amsterdam .
3.
Fedrick
J
Alberman
E D
. (1972 ) British Medical Journal , ii , 485 .
