Samah Zidan, Hoda Sayed Mohamed, Hind Ahmed Mahmoud Elsawi, Fatma Aboulkhair Farag, and Manar Fathy Hamza. “Effect of Incentive Spirometer on Post COVID-19 patient’s Respiratory Outcomes”. Innovative Journal of Medical and Health Sciences, vol. 12, no. 08, Aug. 2022, pp. 1955-66, http://innovativejournal.in/index.php/ijmhs/article/view/3479.