Khan, Zafar ullah, and Kamran Zamurrad Malik. “CHRONIC MAXILLARY SINUSITIS, AN UNCOMMON AETIOLOGICAL FACTOR OF HEADACHE”. Pakistan Armed Forces Medical Journal 56, no. 2 (June 30, 2006): 138–142. Accessed June 16, 2025. https://www.pafmj.org/PAFMJ/article/view/1507.