@article{GDZPPN002226413,
title = {Dupin'sche Hyperfl\"achen in E4.},
journal = {Manuscripta mathematica},
volume = {53},
year = {1985},
pages = {89-120},
zbl = {0572.53028},
url = {http://dml.mathdoc.fr/item/GDZPPN002226413}
}
Pinkall, Ulrich. Dupin'sche Hyperflächen in E4.. Manuscripta mathematica, Tome 53 (1985) pp. 89-120. http://gdmltest.u-ga.fr/item/GDZPPN002226413/