1. When do perinatal deaths in multiple pregnancies occur?;Fliegner;Aust N Z J Obstet Gynaecol,1989
2. Epidemiology and diagnosis of twin gestation;Hollenbach;Clin Obstet Gynecol,1990
3. Contribution of twin pregnancy to perinatal mortality and fetal growth retardation after birth;Manlan;Can Med Assoc J,1978
4. The Birmingham twin survey;Cameron;Proc R Soc Med,1968
5. Twin gestation;Pretorius,1990