@article{10_14708_cm_v27i1_6191,
     author = {I. Kubiaczyk},
     title = {Existence theorem for multivalued hyperbolic equation},
     journal = {Commentationes Mathematicae},
     pages = { 115--119},
     publisher = {mathdoc},
     volume = {27},
     number = {1},
     year = {1987},
     doi = {10.14708/cm.v27i1.6191},
     language = {pl},
     url = {http://geodesic.mathdoc.fr/articles/10.14708/cm.v27i1.6191/}
}