@article{GDZPPN002314649, title = {The Oblique Derivative Problem. I.}, journal = {Mathematische Annalen}, volume = {229}, year = {1977}, pages = {267-278}, zbl = {0362.35025}, url = {http://dml.mathdoc.fr/item/GDZPPN002314649} }
Winzell, Bengt. The Oblique Derivative Problem. I.. Mathematische Annalen, Tome 229 (1977) pp. 267-278. http://gdmltest.u-ga.fr/item/GDZPPN002314649/