Jimrise, O., S. W. Musundi, and M. O. Okongo. “STABILITY ANALYSIS OF THE MODIFIED ADVECTION-DISPERSION MODEL FOR NITRATE LEACHING INTO GROUNDWATER”. Journal of Progressive Research in Mathematics, Vol. 14, no. 2, Oct. 2018, pp. 2334-40, http://scitecresearch.com/journals/index.php/jprm/article/view/1570.