@article{1077379120, author = {Robertson, M. S.}, title = {The sum of univalent functions}, journal = {Duke Math. J.}, volume = {37}, number = {1}, year = {1970}, pages = { 411-419}, language = {en}, url = {http://dml.mathdoc.fr/item/1077379120} }
Robertson, M. S. The sum of univalent functions. Duke Math. J., Tome 37 (1970) no. 1, pp. 411-419. http://gdmltest.u-ga.fr/item/1077379120/