@article{DAN_1991_318_5_a14,
     author = {I. M. Novitskii},
     title = {Reduction of linear operators in $L_2$ to integral form with},
     journal = {Doklady Akademii Nauk},
     pages = {1088--1091},
     publisher = {mathdoc},
     volume = {318},
     number = {5},
     year = {1991},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1991_318_5_a14/}
}