@misc{ZNSL_1971_23_a0,
     title = {Preface},
     journal = {Zapiski Nauchnykh Seminarov POMI},
     pages = {5--6},
     publisher = {mathdoc},
     volume = {23},
     year = {1971},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/ZNSL_1971_23_a0/}
}