@article{ZNSL_1969_13_a0,
     author = {V. M. Kalinin and O. V. Shalaevskii},
     title = {Preface},
     journal = {Zapiski Nauchnykh Seminarov POMI},
     pages = {4},
     publisher = {mathdoc},
     volume = {13},
     year = {1969},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/ZNSL_1969_13_a0/}
}