@article{EJDE_2005__2005__a4,
     author = {Serag,  Hassan M. and El-Zahrani,  Eada A.},
     title = {Maximum principle and existence of positive solutions for nonlinear systems on \(\mathbb {R^N\)}},
     journal = {Electronic journal of differential equations},
     year = {2005},
     volume = {2005},
     zbl = {1140.35366},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/EJDE_2005__2005__a4/}
}