@article{MAN_1977__229_163023,
     author = {Bengt Winzell},
     title = {The {Oblique} {Derivative} {Problem.} {I.}},
     journal = {Mathematische Annalen},
     pages = {267--278},
     publisher = {mathdoc},
     volume = {229},
     year = {1977},
     zbl = {0362.35025},
     url = {http://geodesic.mathdoc.fr/item/MAN_1977__229_163023/}
}