Stuart W. Piggott, Prehistoric India to WOO B.C. (Harmondsworth: Penguin Books, 1950), p.37; Robert Eric Mortimer Wheeler, Early India and Pakistan to Ashoka (London: Thames & Hudson, 1959), pp.80-92; D.H.Gordon, TJie Prehistoric Background of Indian Culture (Bombay: N.M.Tripathi, Ltd., 1958), pp.26-33.
