M. Memon1, M. Saleem Akhtar2, K. Suleman Memon1, and D. Stüben3, “Phosphorus Forms in the Indus River Alluvial and Loess, Shale and Limestone Derived Residual Soils”, ajc, vol. 23, no. 5, pp. 1952–1962, Jan. 2011.