1. The relationship between artificial termination of pregnancy and abortion or premature birth;Moriyama,1966
2. The influence of artificial abortion on delivery;Furusawa,1966
3. The association of multiple induced abortions with subsequent prematurity and spontaneous abortion;Roht;Acta Obstet. Gynaecol. Jpn,1976
4. Influence of induced abortion on gestational duration in subsequent pregnancies;Van der Slikke;Br. Med. J,1978