RT Journal Article SR Electronic T1 Recent secular trends in multiple birth rates JF Archives of Disease in Childhood - Fetal and Neonatal Edition JO Arch Dis Child Fetal Neonatal Ed FD BMJ Publishing Group Ltd and Royal College of Paediatrics and Child Health SP F77 OP F77 DO 10.1136/fn.77.1.F77 VO 77 IS 1 A1 WILLIAM H JAMES YR 1997 UL http://fn.bmj.com/content/77/1/F77.1.abstract AB