@article{DE_1992_28_4_a16,
     author = {D. G. Orlovskii},
     title = {Fredholm solvability of inverse boundary value problems for second-order abstract differential equations},
     journal = {Differencialʹnye uravneni\^a},
     pages = {687--697},
     publisher = {mathdoc},
     volume = {28},
     number = {4},
     year = {1992},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1992_28_4_a16/}
}