@article{CM_1968__20__70_0,
     author = {Goodstein, R. L.},
     title = {Existence in mathematics},
     journal = {Compositio Mathematica},
     pages = {70--82},
     publisher = {Wolters-Noordhoff Publishing},
     volume = {20},
     year = {1968},
     mrnumber = {224413},
     zbl = {0162.30901},
     language = {en},
     url = {http://archive.numdam.org/item/CM_1968__20__70_0/}
}