%0 Journal Article
%T [unknown]
%J Acta mathematica Universitatis Comenianae
%D 1987
%P 199-202
%V 50-51
%I mathdoc
%U http://geodesic.mathdoc.fr/item/AMUC_1987__50-51_185975/
%F AMUC_1987__50-51_185975