1. Growth and development of twins dissimilar in size at birth;Babson;N Engl J Med,1973
2. Prenatal karyotyping of twins by ultrasonically guided amniocentesis;Bang;Obstet Gynecol,1975
3. Twin pregnancy and erythroblastosis;Beischer;Obstet Gynecol,1969
4. Accurate recording of twin placentation: A plea to the obstetrician;Benirschke;Obstet Gynecol,1961
5. Multiple pregnancy. I;Benirschke;N Engl J Med,1973