Amadi, A.N., Olasehinde, P.I., Yisa, J., Shaibu, I., and Okoye, N.O., “Environmental Geochemistry and Heavy Metal Assessment in Soils, Surface and Groundwater from Eastern Niger-Delta, Nigeria using Multivariate Pollution Indices”, IJSGS, vol. 2, no. 3, p. 15, Sep. 2016.