Erkan, Sanlı, Pelin Öcal, İsmail Cepni, Barbaros Ilıkkan, Merve Barbaros, and Rıza Madazlı. 2006. “Spontaneous Twin Pregnancies Versus Twin Pregnancies Conceived With Assisted Reproductive Technologies”. Gynecology Obstetrics &Amp; Reproductive Medicine 12 (1). Ankara, TR:23-26. https://gorm.com.tr/index.php/GORM/article/view/555.