Elsayed M. E. Zayed  & H. M. Abdel Rahman . (2019). The Homotopy Perturbation Method and the Adomian Decomposition Method for the Nonlinear Coupled Equations.
            <i>Journal of Partial Differential Equations</i>. <i>22</i> (4).
            334-351.
         doi:10.4208/jpde.v22.n4.3