@article{1077472103,
author = {Wang, Hsien-Chung},
title = {A projective invariant of a non-holonomic surface},
journal = {Duke Math. J.},
volume = {10},
number = {1},
year = {1943},
pages = { 565-574},
language = {en},
url = {http://dml.mathdoc.fr/item/1077472103}
}
Wang, Hsien-Chung. A projective invariant of a non-holonomic surface. Duke Math. J., Tome 10 (1943) no. 1, pp. 565-574. http://gdmltest.u-ga.fr/item/1077472103/