1. Increasing trend in plural births in the United States;Jewell;Obstet Gynecol,1995
2. The changing pattern of multiple births in the United States: maternal and infant characteristics, 1973 and 1990;Luke;Obstet Gynecol,1994
3. Monozygotic twinning and structural defects;Schinzel;J Pediatr,1979
4. Contribution of twin pregnancy to perinatal mortality and fetal growth retardation: reversal of growth retardation after birth;Manlan;CMAJ,1978
5. Polyhydramnios: ultrasonically detected prevalence and neonatal outcome;Hill;Obstet Gynecol,1987