@article{DE_1969_5_7_a12,
     author = {S. G. Krein and I. M. Kulikov},
     title = {The {Maxwell-Leontovi\v{c}} operator},
     journal = {Differencialʹnye uravneni\^a},
     pages = {1275--1282},
     year = {1969},
     volume = {5},
     number = {7},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1969_5_7_a12/}
}