@article{CM_1968__20__133_0,
     author = {Lorenzen, P.},
     title = {Constructive mathematics as a philosophical problem},
     journal = {Compositio Mathematica},
     pages = {133--142},
     publisher = {Wolters-Noordhoff Publishing},
     volume = {20},
     year = {1968},
     mrnumber = {224426},
     zbl = {0169.29302},
     language = {en},
     url = {http://www.numdam.org/item/CM_1968__20__133_0/}
}