T. C. Guleria, S. Mohindroo, N. K. Mohindroo, and R. K. Azad, “Prevalence and etiology of hearing impairment in urban area of Shimla, Himachal Pradesh, India: a cross sectional observational study”, Int J Res Med Sci, vol. 5, no. 4, pp. 1252–1255, Mar. 2017.