@article{DAN_1970_193_3_a14,
     author = {V. N. Shuhman},
     title = {The {Cauchy} problem for not strictly hyperbolic equations},
     journal = {Doklady Akademii Nauk},
     pages = {551--553},
     publisher = {mathdoc},
     volume = {193},
     number = {3},
     year = {1970},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1970_193_3_a14/}
}