@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/