@article{10_4171_dm_108,
     author = {J\"org Winkelmann},
     title = {Realizing countable groups as automorphism groups of {Riemann} surfaces},
     journal = {Documenta mathematica},
     pages = {413--417},
     year = {2001},
     volume = {6},
     doi = {10.4171/dm/108},
     url = {http://geodesic.mathdoc.fr/articles/10.4171/dm/108/}
}