@article{MMO_1977_34_a6,
     author = {G. V. \v{Z}danova and M. V. Fedoryuk},
     title = {Asymptotic theory of systems of ordinary second order differential equations, and the scattering problem},
     journal = {Trudy Moskovskogo matemati\v{c}eskogo ob\^{s}estva},
     pages = {213--242},
     publisher = {mathdoc},
     volume = {34},
     year = {1977},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MMO_1977_34_a6/}
}