1. Leakey, R.A. (1981): The Making of Mankind, Abacus, New York, pp. 35
2. Nair, Shantha N. (2008): Echoes of Ancient Indian Wisdom, Pustak Mahal, New Delhi, pp. 306
3. Shanti Parva : 109-9-11
4. Karna Parva : Ch. 69 Verse 58
5. Manu Smriti : II : 4
6. Manu Smriti : XII : 3 -7
7. Manu Smriti : XII : 10-11
8. Rao, M.V.K. (1979): Studies in Kautilya, Munshiram Manoharlal Publishe,
Pvt. Ltd., New Delhi.
9. Manu Smriti : 12-35
10. Manu Smriti : 8-84
11. Manu Smriti : 9-42
12. Kosambi, D.D.(1970): The Culture and Civilization of Ancient India in Historical Outline, Vikas Publications, Delhi, pp. 172
13. Bhagvadgita : II : 62-63,
14. Saund, Dalip Singh, (1930), My Mother India, The Pacific Coast Khalsa Diwan Society, California, pg. 190.