@article{INTA_1988_26_a2,
     author = {A. A. Agrachev},
     title = {The topology of quadratic mappings and {Hessians} of smooth mappings},
     journal = {Itogi Nauki i Tekhniki. Seriya Algebra. Geometriya. Topologiya },
     pages = {85--124},
     publisher = {mathdoc},
     volume = {26},
     year = {1988},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/INTA_1988_26_a2/}
}