@article{1102948654, author = {Hayman, W. K.}, title = {Differential inequalities and local valency.}, journal = {Pacific J. Math.}, volume = {49}, number = {2}, year = {1973}, pages = { 117-137}, language = {en}, url = {http://dml.mathdoc.fr/item/1102948654} }
Hayman, W. K. Differential inequalities and local valency.. Pacific J. Math., Tome 49 (1973) no. 2, pp. 117-137. http://gdmltest.u-ga.fr/item/1102948654/