Dr. Jaimin A Mansuriya, Dr. Jignasa J Mansuriya, Dr. Alok Pritam. RELATIONSHIP BETWEEN SEVERE VITAMIN D DEFICIENCY AND FREQUENCY OF COPD EXACERBATIONS: A RETROSPECTIVE COHORT STUDY AT A TERTIARY CARE CENTER IN NORTH INDIA. J Popl Ther Clin Pharmacol. 2025;32(9):1582-1590. doi:10.53555/sp8cyq47