Kaushaljeet Gill. “Effect of Flow Versus Volume Incentive Spirometry on Chest Expansion in Coronary Artery Bypass Graft Surgery Patients: A Comparative Study”. International Journal of Allied Medical Sciences and Clinical Research, vol. 8, no. 2, Aug. 2020, pp. 411-23, doi:10.61096/ijamscr.v8.iss2.2020.411-423.