C. . Chongkolwatana, C. . Metheetrairut, S. . Chongvisal, and P. . Keskool, “The Sensitivity of Transnasal Biopsy at Random for The Diagnosis of Nasopharyngeal Carcinoma”, Siriraj Med J, vol. 51, no. 4, pp. 244–251, Apr. 1999.