K. Haj Hammo, M., D. J. Al layla, and R. M. A. Al Hayali. “Prevalence of Gastro-Oesophageal Reflux Symptoms in Patients With COPD”. Annals of the College of Medicine, Mosul, vol. 32, no. 1, Dec. 2006, pp. 18-22, doi:10.33899/mmed.2006.30122.