@article{GDZPPN002245493,
title = {Geometrische Interpretation der Differentialgleichnng P d x + Qdy + Rdz = 0},
journal = {Mathematische Annalen},
volume = {16},
year = {1880},
pages = {556-559},
zbl = {12.0278.01},
url = {http://dml.mathdoc.fr/item/GDZPPN002245493}
}
Voss. Geometrische Interpretation der Differentialgleichnng P d x + Qdy + Rdz = 0. Mathematische Annalen, Tome 16 (1880) pp. 556-559. http://gdmltest.u-ga.fr/item/GDZPPN002245493/