@article{DAN_1978_242_3_a9,
     author = {V. G. Romanov},
     title = {Inverse problems for hyperbolic equations and energy inequalities},
     journal = {Doklady Akademii Nauk},
     pages = {541--544},
     year = {1978},
     volume = {242},
     number = {3},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1978_242_3_a9/}
}