@article{SM_1972_17_4_a9,
     author = {A. S. Kalashnikov},
     title = {A~problem without initial conditions for linear degenerate hyperbolic equations of second order with infinite domain of dependence},
     journal = {Sbornik. Mathematics},
     pages = {603--616},
     publisher = {mathdoc},
     volume = {17},
     number = {4},
     year = {1972},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/SM_1972_17_4_a9/}
}