Abstract

References
1.
Clarke
C A
. (1970 ) Clin. Genet.
1 , 183 .
2.Combined Study from Centres in England and Baltimore (1971 ) Brit. med. J.
ii , 607 .
3.
Woodrow
J C
Clarke
C A
McConnell
R B
Towers
S H
Donohoe
W T A
. (1971 ) Brit. med. J.
ii , 610 .
