Yaro, A., L. Abdulrashid, and Y. Sani. “Estimation of Lead, Cadmium and Copper in Urban Irrigation Sites in Katsina Urban Area, Northern Nigeria”. International Journal For Research In Applied And Natural Science, vol. 3, no. 6, June 2017, pp. 32-43, doi:10.53555/ans.v3i6.83.