%0 Journal Article %A Lassak, Marek %T A general notion of extreme subset %J Compositio Mathematica %D 1986 %P 61-72 %V 57 %N 1 %I Martinus Nijhoff Publishers %U http://www.numdam.org/item/CM_1986__57_1_61_0/ %G en %F CM_1986__57_1_61_0