@article{DE_1988_24_11_a11,
     author = {N. I. Popivanov},
     title = {Overdetermined problems for the wave equation and their nonlocal regularization},
     journal = {Differencialʹnye uravneni\^a},
     pages = {1941--1954},
     publisher = {mathdoc},
     volume = {24},
     number = {11},
     year = {1988},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1988_24_11_a11/}
}