Venkataraya Chari, K., R. Jagadiswara Rao, and M. G. Chakrapani Naidu. “Fluctuations in the Fluoride Content of Ground Waters in Certain Fluorosis-Endemic Villages of Ongole District, Andhra Pradesh”. The Indian Journal of Nutrition and Dietetics, vol. 8, no. 1, Jan. 1971, pp. 5-8, http://www.informaticsjournals.com/index.php/ijnd/article/view/11404.