@article{MAN_1979__243_182798,
     author = {Shuzo Izumi},
     title = {The {Exterior} {Derivation} and the {Orders} of {Differential} {Forms} on {Contractible} {Algebras.}},
     journal = {Mathematische Annalen},
     pages = {31--36},
     publisher = {mathdoc},
     volume = {243},
     year = {1979},
     zbl = {0397.58001},
     url = {http://geodesic.mathdoc.fr/item/MAN_1979__243_182798/}
}