Siahaan, Laura A, Ari F Syam, Marcellus Simadibrata, and Siti Setiati. 2017. “The Validity and Reliability Test of the Indonesian Version of Gastroesophageal Reflux Disease Quality of Life (GERD-QOL) Questionnaire”. Acta Medica Indonesiana 49 (1):3-9. http://www.actamedindones.org/index.php/ijim/article/view/227.