Dogan, U., and M. Tahir Oruc. “Evaluation of Changes in Vitamin B12, Ferritin, Folic Acid, and Thyroid Hormone Levels After Sleeve Gastrectomy”. Annals of Medical Research, vol. 25, no. 1, May 2021, pp. 0018-21, http://annalsmedres.org/index.php/aomr/article/view/1553.