@article{MZ_1927__26_167920,
     author = {T. Takasu},
     title = {\"Uber konforme {Verallgemeinerungen} der {Bertrandschen} {Kurven}},
     journal = {Mathematische Zeitschrift},
     pages = {157--164},
     publisher = {mathdoc},
     volume = {26},
     year = {1927},
     zbl = {53.0701.01},
     url = {http://geodesic.mathdoc.fr/item/MZ_1927__26_167920/}
}