@article{TMF_1971_8_1_a4,
     author = {V. B. Matveev},
     title = {Invariance principle for generalized wave operators},
     journal = {Teoreti\v{c}eska\^a i matemati\v{c}eska\^a fizika},
     pages = {49--54},
     publisher = {mathdoc},
     volume = {8},
     number = {1},
     year = {1971},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/TMF_1971_8_1_a4/}
}