Upadhyay, A. A., and P. P. Bhide. “Vitamin D and Calcium Deficiency in Otolaryngological Diseases”. International Journal of Otorhinolaryngology and Head and Neck Surgery, vol. 2, no. 4, Sept. 2016, pp. 216-9, doi:10.18203/issn.2454-5929.ijohns20163468.