The Kuru kingdom of the late Vedic period was most likely established around 1200 BC, although there are no datable contemporary references. Pletcher, Kenneth (2010), The History of India, The Rosen Publishing Group, ISBN9781615301225
Samuel, Geoffrey (2010), The Origins of Yoga and Tantra. Indic Religions to the Thirteenth Century, Cambridge University Press
Klein Goldewijk, K., A. Beusen, M. de Vos and G. van Drecht (2011). The HYDE 3.1 spatially explicit database of human induced land use change over the past 12,000 years, Global Ecology and Biogeography20(1): 73–86. doi:10.1111/j.1466-8238.2010.00587.x (pbl.nl).
Jean-Noël Biraben, "Essai sur l'évolution du nombre des hommes", Population 34-1 (1979), 13–25 (p. 22) estimates c. 80 million in 2000 BC and c. 100 million at 1200 BC.
Klein Goldewijk, K., A. Beusen, M. de Vos and G. van Drecht (2011). The HYDE 3.1 spatially explicit database of human induced land use change over the past 12,000 years, Global Ecology and Biogeography20(1): 73–86. doi:10.1111/j.1466-8238.2010.00587.x (pbl.nl).
Jean-Noël Biraben, "Essai sur l'évolution du nombre des hommes", Population 34-1 (1979), 13–25 (p. 22) estimates c. 80 million in 2000 BC and c. 100 million at 1200 BC.