%0 Journal Article %A Frank Beatrous %T Boundary estimates for derivatives of harmonic functions %J Studia Mathematica %D 1991 %P 53-71 %V 98 %N 1 %I mathdoc %U http://geodesic.mathdoc.fr/articles/10.4064/sm-98-1-53-71/ %R 10.4064/sm-98-1-53-71 %G en %F 10_4064_sm_98_1_53_71