@article{AUPCM_2015_14_a10,
     author = {Klimczak, Liliana},
     title = {Two constant sign solutions for a nonhomogeneous {Neumann} boundary value problem},
     journal = {Annales Universitatis Paedagogicae Cracoviensis. Studia Mathematica},
     publisher = {mathdoc},
     number = {14},
     year = {2015},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/AUPCM_2015_14_a10/}
}