%0 Journal Article
%A Pfeffer, W. F.
%T On the Lower Derivate of a Set Function
%J Canadian journal of mathematics
%D 1968
%P 1489-1498
%V 20
%N 1
%U http://geodesic.mathdoc.fr/articles/10.4153/CJM-1968-149-8/
%R 10.4153/CJM-1968-149-8
%F 10_4153_CJM_1968_149_8