@article{1077374666, author = {Turrittin, H. L.}, title = {Reducing the rank of ordinary differential equations}, journal = {Duke Math. J.}, volume = {30}, number = {1}, year = {1963}, pages = { 271-274}, language = {en}, url = {http://dml.mathdoc.fr/item/1077374666} }
Turrittin, H. L. Reducing the rank of ordinary differential equations. Duke Math. J., Tome 30 (1963) no. 1, pp. 271-274. http://gdmltest.u-ga.fr/item/1077374666/