@article{GDZPPN002280051,
title = {Differential Invariants in a General Differential Geometry},
journal = {Mathematische Annalen},
volume = {116},
year = {1939},
pages = {310-333},
zbl = {0020.36905},
url = {http://dml.mathdoc.fr/item/GDZPPN002280051}
}
MichaI, A.D.; Hyers, D.H. Differential Invariants in a General Differential Geometry. Mathematische Annalen, Tome 116 (1939) pp. 310-333. http://gdmltest.u-ga.fr/item/GDZPPN002280051/