@article{1102994734, author = {O'Keefe, Kathleen B.}, title = {On a problem of J. F. Ritt.}, journal = {Pacific J. Math.}, volume = {19}, number = {3}, year = {1966}, pages = { 149-157}, language = {en}, url = {http://dml.mathdoc.fr/item/1102994734} }
O'Keefe, Kathleen B. On a problem of J. F. Ritt.. Pacific J. Math., Tome 19 (1966) no. 3, pp. 149-157. http://gdmltest.u-ga.fr/item/1102994734/