@article{10_4064_cm_18_1_119_124,
     author = {J. Szarski},
     title = {On an overdetermined system of non-linear partial differential equations of the first order},
     journal = {Colloquium Mathematicum},
     pages = {119--124},
     publisher = {mathdoc},
     volume = {18},
     number = {1},
     year = {1967},
     doi = {10.4064/cm-18-1-119-124},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.4064/cm-18-1-119-124/}
}