@article{10_4064_ap105_1_6,
     author = {Shapour Heidarkhani},
     title = {Non-trivial solutions for a class of $(p_1,\dots ,p_n)$-biharmonic
 systems with {Navier} boundary conditions},
     journal = {Annales Polonici Mathematici},
     pages = {65--76},
     publisher = {mathdoc},
     volume = {105},
     number = {1},
     year = {2012},
     doi = {10.4064/ap105-1-6},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.4064/ap105-1-6/}
}