@article{MZ_1987__195_183684,
     author = {Katsumi Nomizu and Ulrich Pinkall},
     title = {On the {Geometry} of {Affine} {Immersions.}},
     journal = {Mathematische Zeitschrift},
     pages = {165--178},
     year = {1987},
     volume = {195},
     zbl = {0629.53012},
     url = {http://geodesic.mathdoc.fr/item/MZ_1987__195_183684/}
}