1. Akpan, A. E., Ugbaja, A. N., & George, N. J. (2013). Integrated geophysical, geochemical and hydrogeological investigation of shallow groundwater resources in parts of the Ikom-Mamfe Embayment and the adjoining areas in Cross River State, Nigeria. Journal of Environmental Earth Sciences, 70, 1435–1456.
2. Aller, L, Bennet, T, Lehr, J.H., Petty, R.J., & Hackett, G. (1987). DRASTIC: a standardized system for evaluating ground water pollution potential using hydrogeologic settings. US EPA, 600/2-87–035.
3. Almasri, M. N. (2008). Assessment of intrinsic vulnerability to contamination for Gaza coastal aquifer, Palestine. Journal of Environmental Management, 88, 577–593.
4. Benkhelil, M. G., Ponsard, J. F., & Saugy, L. (1975). The Bornu-Benue Trough, the Niger Delta and its Offshore: Tectono-sedimentary reconstruction during the Cretaceous and Tertiary from geophysical data and geology. In C. A. Kogbe (Ed.), Geology of Nigeria (pp. 277–309). Lagos: Elizabethan Press.
5. Braga, A. C., Filho, W. M., & Dourado, J. C. (2006). Resistivity (DC) method applied to aquifer protection studies. Revista Brasileira de Geofisica, 24(4), 573–581.