@article{MAT_1972_16_1_a3,
     author = {R. Sakamoto},
     title = {Mixed problems for hyperbolic equations. {II.~Existence} theorems with zero initial datas and energy inequalities with initial datas},
     journal = {Matematika},
     pages = {81--99},
     publisher = {mathdoc},
     volume = {16},
     number = {1},
     year = {1972},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MAT_1972_16_1_a3/}
}