%0 Journal Article %A Lorenzen, P. %T Constructive mathematics as a philosophical problem %J Compositio Mathematica %D 1968 %P 133-142 %V 20 %I Wolters-Noordhoff Publishing %U http://www.numdam.org/item/CM_1968__20__133_0/ %G en %F CM_1968__20__133_0