@article{10_4064_ap_12_2_191_197,
     author = {W. Mlak},
     title = {Estimates of solutions of hyperbolic systems of differential equations in two independent variables},
     journal = {Annales Polonici Mathematici},
     pages = {191--197},
     publisher = {mathdoc},
     volume = {12},
     number = {2},
     year = {1962},
     doi = {10.4064/ap-12-2-191-197},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.4064/ap-12-2-191-197/}
}