@article{CM_1937__4__119_0,
     author = {Johansson, Ingebrigt},
     title = {Der Minimalkalk\"ul, ein reduzierter intuitionistischer Formalismus},
     journal = {Compositio Mathematica},
     publisher = {Johnson Reprint Corporation},
     volume = {4},
     year = {1937},
     pages = {119-136},
     zbl = {0015.24102},
     language = {de},
     url = {http://www.numdam.org/item/CM_1937__4__119_0}
}

Johansson, Ingebrigt. Der Minimalkalkül, ein reduzierter intuitionistischer Formalismus. Compositio Mathematica, Volume 4 (1937) , pp. 119-136. http://www.numdam.org/item/CM_1937__4__119_0/