%0 Journal Article
%A Grätzer, G.
%A Wenzel, G. H.
%T Tolerances, covering systems, and the axiom of choice
%J Archivum mathematicum
%D 1989
%P 27-34
%V 25
%N 1-2
%I mathdoc
%U http://geodesic.mathdoc.fr/item/ARM_1989__25_1-2_a4/
%G en
%F ARM_1989__25_1-2_a4