@article{10_1017_S0017089500007278,
     author = {Tsuyumine, Shigeaki},
     title = {Automorphy factors for a {Hilbert} modular group},
     journal = {Glasgow mathematical journal},
     pages = {231--236},
     year = {1988},
     volume = {30},
     number = {2},
     doi = {10.1017/S0017089500007278},
     url = {http://geodesic.mathdoc.fr/articles/10.1017/S0017089500007278/}
}