1. Monoamniotic twin pregnancy;Colburn;J Reprod Med,1982
2. Multiple gestation;Hays;Clin Obstet Gynecol,1986
3. Monoamniotic twin pregnancy;Timmons;Am J Obstet Gynecol,1963
4. Placental injection studies in twin gestations;Robertson;Am J Obstet Gynecol,1983
5. Rapid B-scan (real-time) ultrasonography in the identification and evaluation of twin pregnancies;Levine;Obstet Gynecol Scand,1980