Rajeev, K., S., R., S., C. C., Shenoy, S. B. and ., J. (2018) “Anatomical variations of maxillary and ethmoid sinus in chronic rhinosinusitis”, International Journal of Otorhinolaryngology and Head and Neck Surgery, 4(4), pp. 1008–1012. doi: 10.18203/issn.2454-5929.ijohns20182703.