Khawaja Kamal Nasir, K. K. N., F. M. . Faraz Mansoor, S. H. W. Shahzad Hussain Waqar, S. Z. A. K. Shahab Zahid Ahmed Khan, and R. J. Rakhshanda Jabeen. “Percutaneous Dilatational Tracheostomy: A Prospective Analysis Among ICU Patients”. Journal of Rawalpindi Medical College, vol. 24, no. 1, Mar. 2020, http://www.journalrmc.com/index.php/JRMC/article/view/1360.