Yusuf, F.; Prasetyo, A.; Karlowee, V.; Astuti, M. D. K.; Nur, R. W. Increased Expression of PD-L1 in Undifferentiated Non Keratinizing Squamous Cell Carcinoma Nasopharynx. Medica Hospitalia J. Clin. Med. 2021, 8, 200-206.