@article{1077489791,
author = {Dearborn, Donald C.},
title = {Inequalities among the invariants of pfaffian systems},
journal = {Duke Math. J.},
volume = {2},
number = {1},
year = {1936},
pages = { 705-711},
language = {en},
url = {http://dml.mathdoc.fr/item/1077489791}
}
Dearborn, Donald C. Inequalities among the invariants of pfaffian systems. Duke Math. J., Tome 2 (1936) no. 1, pp. 705-711. http://gdmltest.u-ga.fr/item/1077489791/