@article{10_4171_dm_230,
     author = {Alexander Schmidt},
     title = {Rings of integers of type $K(\pi,1)$},
     journal = {Documenta mathematica},
     pages = {441--471},
     year = {2007},
     volume = {12},
     doi = {10.4171/dm/230},
     url = {http://geodesic.mathdoc.fr/articles/10.4171/dm/230/}
}