@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/