@article{IM_1981__65_142836,
     author = {W.M. Goldmann and Morris W. Hirsch},
     title = {A {Generalization} of {Bieberbach's} {Theorem.}},
     journal = {Inventiones mathematicae},
     pages = {1--12},
     publisher = {mathdoc},
     volume = {65},
     year = {1981},
     url = {http://geodesic.mathdoc.fr/item/IM_1981__65_142836/}
}