Al-Hawasy, J. A., and M. A. Jawad. “Approximation Solution of Nonlinear Parabolic Partial Differential Equation via Mixed Galerkin Finite Elements Method With the Crank-Nicolson Scheme”. Iraqi Journal of Science, Vol. 60, no. 2, Feb. 2019, pp. 353-61, https://ijs.uobaghdad.edu.iq/index.php/eijs/article/view/602.