Z. W. Aziz, A. M. Mahmood, Z. O. Yahiya, and W. M. Taib Al-Nuaimy, “Correlation Between Programmed Cell Death Ligand1 (PD-L1) Expression and Clinical Parameters in Colorectal Carcinoma”, J. Contemp. Med. Sci., vol. 6, no. 4, pp. 161–167, Aug. 2020.