1. Twin gestation;Keith,1979
2. Prognosis for the babies, early and late;Farr,1975
3. Stillbirth and neonatal mortality in twin pregnancy;Anderson;Br. J. Obstet. Gynaecol.,1956
4. The twin delivery—Factors influencing second twin mortality;Little;Obstet. Gynecol. Surv.,1958
5. Twin pregnancy-Complications and treatment;Powers;Obstet. Gynecol.,1973