@article{DAN_1957_112_3_a2,
     author = {G. Gussi and V. Po\'enaru and C. Foias},
     title = {Direct method in the {Cauchy} problem for a quasi-linear hyperbolic equation involving two independent variables},
     journal = {Doklady Akademii Nauk},
     pages = {381--382},
     publisher = {mathdoc},
     volume = {112},
     number = {3},
     year = {1957},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1957_112_3_a2/}
}