@article{PPN51697307X+dmdlog29, title = {1.) Gau\ss , Lobatcheffsky, Bolyai.}, booktitle = {Gehalten w\"ahrend des Wintersemesters 1889 - 90 Vorlesung 1}, series = {GDML\_Books}, year = {1892}, pages = {171}, url = {http://dml.mathdoc.fr/item/PPN51697307X+dmdlog29} }
(éd.). 1.) Gauß, Lobatcheffsky, Bolyai., dans Gehalten während des Wintersemesters 1889 - 90 Vorlesung 1, GDML_Books, (1892), p. 171. http://gdmltest.u-ga.fr/item/PPN51697307X+dmdlog29/