Khan, Abdul Rehman, and Farzana Siddiqui. 2020. “Regional Prevalence of Different Types of Sinusitis at a Tertiary Care Centre in Northern India”. International Journal of Otorhinolaryngology and Head and Neck Surgery 6 (5):969-73. https://doi.org/10.18203/issn.2454-5929.ijohns20201697.