@article{MS2_1958__6_165672,
     author = {Vidar Thom\'ee},
     title = {Existence {Proofs} for {Mixed} {Problems} for {Hyperbolic} {Differential} {Equations} in {Two} {Independent} {Variables} by {Means} of the {Continuity} {Method.}},
     journal = {Mathematica Scandinavica},
     pages = {5--32},
     publisher = {mathdoc},
     volume = {6},
     year = {1958},
     zbl = {0089.30204},
     url = {http://geodesic.mathdoc.fr/item/MS2_1958__6_165672/}
}