@article{EJDE_2012__2012__a28,
     author = {Afrouzi,  Ghasem A. and Mirzapour,  Maryam and Zhang,  Qihu},
     title = {Simplicity and stability of the first eigenvalue of a \((p;q)\) {Laplacian} system},
     journal = {Electronic journal of differential equations},
     year = {2012},
     volume = {2012},
     zbl = {1238.35079},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/EJDE_2012__2012__a28/}
}