%0 Journal Article
%A Preiss, David
%A Zajíček, Luděk
%T On the symmetry of approximate Dini derivates of arbitrary functions
%J Commentationes Mathematicae Universitatis Carolinae
%D 1982
%P 691-697
%V 23
%N 4
%I mathdoc
%U http://geodesic.mathdoc.fr/item/CMUC_1982__23_4_a6/
%G en
%F CMUC_1982__23_4_a6