@article{PPN592509354+DMDLOG_0005, title = {Ebene Trigonometrie.}, booktitle = {Ebene und sph\"arische Trigonometrie Theil 3}, series = {GDML\_Books}, publisher = {Hirt}, address = {Breslau}, year = {1874}, pages = {15}, url = {http://dml.mathdoc.fr/item/PPN592509354+DMDLOG_0005} }
(éd.). Ebene Trigonometrie., dans Ebene und sphärische Trigonometrie Theil 3, GDML_Books, (1874), p. 15. http://gdmltest.u-ga.fr/item/PPN592509354+DMDLOG_0005/