RT Journal Article SR Electronic T1 Causes of birth asphyxia and trauma JF Canadian Medical Association Journal JO CMAJ FD Canadian Medical Association SP 1077 OP 1085 VO 94 IS 21 A1 J. R. O'Brien A1 R. H. Usher A1 G. B. Maughan YR 1966 UL http://www.cmaj.ca/content/94/21/1077.abstract