1. Twin pregnancies - a continuing perinatal challenge;Hawrylyshyn;Obstet Gynecol,1982
2. Twin gestations, I: antenatal care and complications;Kovacs;Obstet Gynecol,1989
3. A case-control study of 1253 twin pregnancies from a 1982-1987 perinatal database;Spellacy;Obstet Gynecol,1990
4. Antepartum fetal heart rate monitoring in multiple pregnancy;Bailey;Br J Obstet Gynaecol,1980
5. Simultaneous nonstress fetal heart rate testing in twin pregnancy;Devoe;Obstet Gynecol,1981