↑Kenoyer, Jonathan Mark (1998). Ancient cities of the Indus Valley Civilization. Oxford University Press. p. 96. ISBN0-19-577940-1. Another source of gold was along the Oxus river valley in northern Afghanistan where a trading colony of the Indus cities has been discovered at Shortughai. Situated far from the Indus Valley itself, this settlement may have been established to obtain gold, copper, tin and lapis lazuli, as well as other exotic goods from Central Asia.
↑Bowersox, Gary W.; Chamberlin, Bonita E. Ph. D. (1995). "Gemstones of Afghanistan". Tucson, AZ: Geoscience Press: 52. {{cite journal}}: Cite journal requires |journal= (help). "During the height of the Indus valley civilization about 2000 B.C. , the Harappan colony of Shortugai was established near the lapis mines."