@article{CMH_1981__56_139882,
     author = {D. Fried and W. Goldman and M.W. Hirsch},
     title = {Affin manifolds with nilpotent holonomy.},
     journal = {Commentarii mathematici Helvetici},
     pages = {487--523},
     publisher = {mathdoc},
     volume = {56},
     year = {1981},
     zbl = {0516.57014},
     url = {http://geodesic.mathdoc.fr/item/CMH_1981__56_139882/}
}