Danish Abdul Aziz, Syeda Khadija Fatima and Hasan Nawaz Tahir 2021. Risk factors leading to pulmonary exacerbation in patients with cystic fibrosis: A systematic review. Journal of the Pakistan Medical Association. 71, 9 (Jul. 2021), 2217–2223. DOI:https://doi.org/10.47391/JPMA.04-515.