Tosun, Alptekin, Enis Özkaya, Vakkas Korkmaz, and Yasemin Çekmez. 2013. “Ductus Venosus Doppler S/D Value Adjusted Alfa Fetoprotein Levels to Decrease False Positive Rates”. Gynecology Obstetrics &Amp; Reproductive Medicine 19 (3). Ankara, TR:153-56. https://gorm.com.tr/index.php/GORM/article/view/208.