@article{DE_1997_33_10_a12,
     author = {F. E. Lomovtsev},
     title = {Second-order hyperbolic differential equations with discontinuous operator coefficients},
     journal = {Differencialʹnye uravneni\^a},
     pages = {1394--1403},
     publisher = {mathdoc},
     volume = {33},
     number = {10},
     year = {1997},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1997_33_10_a12/}
}