@article{MMO_1956_5_a8,
     author = {I. S. Iokhvidov and M. G. Krein},
     title = {Spectral theory of operators in space with indefinite {metric.~I}},
     journal = {Trudy Moskovskogo matemati\v{c}eskogo ob\^{s}estva},
     pages = {367--432},
     publisher = {mathdoc},
     volume = {5},
     year = {1956},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MMO_1956_5_a8/}
}