Jain, D. P., D. R. Jain, D. A. K. Jain, D. M. Jindal, and D. R. Dixit. “Aging and Its Theories: Aging and Its Theories”. National Journal of Integrated Research in Medicine, vol. 3, no. 2, June 2012, pp. 170-3, doi:10.70284/njirm.v3i2.292.