1. Retained second twin in Ibadan: Its fact and management;Adeleye;American Journal of Obstetrics and Gynecology,1972
2. Caesarean section for twin pregnancy in Ibadan, Nigeria;Adewienmi;International Surgery,1977
3. Twin pregnancy: A review of 472 cases;Bender;Journal of Obstetrics and Gynaecology of the British Empire,1952
4. The value of simultaneously applied hormonal and ultrasonic methods in twin pregnancies, Serano Symposium No. 35;Brugnoli,1980
5. Frequency of twins;Bulmer,1970