Nasir Ali Khan, et al. “OUTCOMES OF OFF-PUMP VERSUS ON-PUMP CORONARY ARTERY BYPASS GRAFTING FOR ISCHEMIC HEART DISEASE IN PATIENTS OVER SEVENTY YEARS OF AGE”. Pakistan Armed Forces Medical Journal, vol. 66, no. SUPPL-1, Dec. 2016, pp. S143-48, https://pafmj.org/PAFMJ/article/view/11791.