Gharib, A.; Forootan, M.; Sharifzadeh, M.; Abdi, S.; Darvishi, M.; Eghbali, A. Diagnostic Efficacy of 24-Hr Esophageal PH Monitoring in Patients With Refractory Gastroesophageal Reflux Disease. Open Access Maced J Med Sci 2018, 6, 1235-1238.