@article{MZ_1971__122_171605,
     author = {Nickolas Heerema},
     title = {Exponential {Automorphisms} of {Complete} {Local} {Rings.}},
     journal = {Mathematische Zeitschrift},
     pages = {299--306},
     publisher = {mathdoc},
     volume = {122},
     year = {1971},
     zbl = {0209.07603},
     url = {http://geodesic.mathdoc.fr/item/MZ_1971__122_171605/}
}