Demirtürk, F., H. Aytan, A. Çalışkan, Özdemir Himmetoğlu, and T. Güngör. “Maternal Iron, Copper, Magnesium and Calcium Levels in Preterm Delivery and the Effect of These Trace Elements on Birth Weight”. Gynecology Obstetrics &Amp; Reproductive Medicine, vol. 12, no. 1, Apr. 2006, pp. 4-7, https://gorm.com.tr/index.php/GORM/article/view/550.