Mahdi, B. M., R. M. Hasan, and W. Hazim. “Human Leukocyte Antigen HLA-DRB1 Determinants Susceptibility to Gastroesophageal Reflux Disease”. Journal of Medicine, vol. 19, no. 1, Dec. 2017, pp. 3-9, doi:10.3329/jom.v19i1.34832.