@article{GDZPPN00232914X, title = {On the Boundary Derivative for Univalent Functions.}, journal = {Mathematische Annalen}, volume = {275}, year = {1986}, pages = {499-504}, zbl = {0596.30027}, url = {http://dml.mathdoc.fr/item/GDZPPN00232914X} }
Pommerenke, Ch. On the Boundary Derivative for Univalent Functions.. Mathematische Annalen, Tome 275 (1986) pp. 499-504. http://gdmltest.u-ga.fr/item/GDZPPN00232914X/