Tegnoor, M. S., George, J. W., George, W., & Joshi, R. (2017). Comparative study between diagnostic nasal endoscopy and computed tomography of PNS in sino nasal diseases. International Journal of Otorhinolaryngology and Head and Neck Surgery, 3(4), 972–978. https://doi.org/10.18203/issn.2454-5929.ijohns20174317