§.7. Flächen II. Ordnung.
Neuere Geometrie Theil 1, GDML_Books, (1867), p. 168 / Harvested from
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@article{PPN592025055+DMDLOG_0010,
     title = {\S .7. Fl\"achen II. Ordnung.},
     booktitle = {Neuere Geometrie Theil 1},
     series = {GDML\_Books},
     publisher = {Deichert},
     address = {Erlangen},
     year = {1867},
     pages = {168},
     url = {http://dml.mathdoc.fr/item/PPN592025055+DMDLOG_0010}
}

 (éd.). §.7. Flächen II. Ordnung., dans Neuere Geometrie Theil 1, GDML_Books,  (1867), p. 168. http://gdmltest.u-ga.fr/item/PPN592025055+DMDLOG_0010/