@article{ELMA_1977__32_141189,
     author = {E. Hartmann},
     title = {\"Ubergangsfl\"achen bei {Regelschraubfl\"achen.}},
     journal = {Elemente der Mathematik},
     pages = {32--36},
     publisher = {mathdoc},
     volume = {32},
     year = {1977},
     language = {de},
     url = {http://geodesic.mathdoc.fr/item/ELMA_1977__32_141189/}
}