%0 Journal Article %A W. Mlak %T The epidermic effect for differential inequalities of the first order %J Annales Polonici Mathematici %D 1956 %P 157-164 %V 3 %N 1 %I mathdoc %U http://geodesic.mathdoc.fr/articles/10.4064/ap-3-1-157-164/ %R 10.4064/ap-3-1-157-164 %G en %F 10_4064_ap_3_1_157_164