Liamidi A. Leadi  & Aboubacar Marcos . (2019). Maximum Principle for Nonlinear Cooperative Elliptic Systems on <em>R</em><sup>N</sup>.
            <i>Journal of Partial Differential Equations</i>. <i>24</i> (3).
            264-280.
         doi:10.4208/jpde.v24.n3.3