Ashfaq, Muhammad, et al. “EARLY MORTALITY & MORBIDITY IN MITRAL VALVE REPLACEMENT WITH TOTAL SUB-VALVULAR APPARATUS PRESERVATION, PARTIAL PRESERVATION AND NO PRESERVATION - A COMPARATIVE STUDY”. Pakistan Armed Forces Medical Journal, vol. 70, no. Suppl-4, Jan. 2021, pp. S715-20, doi:10.51253/pafmj.v70iSuppl-4.6006.