@article{PORMA_1959__18_3_114821,
     author = {Haupt, Otto},
     title = {Ordnungs-und infinitesimalgeometrische probleme. {Versuch} einer {Klassifikation}},
     journal = {Portugaliae mathematica},
     pages = {167--175},
     year = {1959},
     volume = {18},
     number = {3},
     mrnumber = {0126744},
     zbl = {0097.38001},
     language = {de},
     url = {http://geodesic.mathdoc.fr/item/PORMA_1959__18_3_114821/}
}