The Ancient Indus Valley: New Perspectives, Jane McIntosh, pp. 167-168, ABC-CLIO, 2008, ISBN 978-1-57607-907-2, ... The importance to the Harappans of resources from the north is indicated by the fact that, rather than merely sending traders to the region, they established an Indus trading outpost at Shortugai, at the confluence of the Kokcha and Amu Darya Rivers in Afghanistan, to facilitate their procurement of local resources. As well as lapis lazulim these resources included tin and gold ...