@article{IM2_1989_33_3_a0,
     author = {A. V. Isaev and M. A. Mishchenko},
     title = {Classification of spherical tube hypersurfaces having one minus in the signature of the {Levi} form},
     journal = {Izvestiya. Mathematics },
     pages = {441--472},
     publisher = {mathdoc},
     volume = {33},
     number = {3},
     year = {1989},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/IM2_1989_33_3_a0/}
}