@article{MZM_1988_44_1_a14,
     author = {A. V. Isaev and M. A. Mishchenko},
     title = {Affine classification of tube quadrics having one minus in the {Levi} form},
     journal = {Matemati\v{c}eskie zametki},
     pages = {145--146},
     publisher = {mathdoc},
     volume = {44},
     number = {1},
     year = {1988},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MZM_1988_44_1_a14/}
}