@article{DE_1991_27_8_a4,
     author = {E. K. Kostousova},
     title = {On the weak observability property for the one-dimensional wave equation with a point nonstationary observation operator},
     journal = {Differencialʹnye uravneni\^a},
     pages = {1318--1325},
     publisher = {mathdoc},
     volume = {27},
     number = {8},
     year = {1991},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1991_27_8_a4/}
}