Abstract
References
1.
Hobbs
J R
, (1969 ) British Journal of Hæmatology
16 , 599
2.Medical Research Council (1971 ) British Medical Journal
i , 640
3.
Peto
R
, (1971 ) British Medical Journal
ii , 324
4.
Wiltshaw
E
, (1971 ) British Medical Journal
ii , 327