Ghasempour, M., Bilan, N., & Rezazadehsaatlou, M. "Positive Expiratory Pressure (PEP) versus Conventional Chest Physiotherapy in Pediatric Patients with Acute Exacerbation of Cystic Fibrosis", Journal of Pediatric Perspectives, 7, 1, 2019, 8881-8888. doi: 10.22038/ijp.2018.34187.3019