@article{10_1017_S0017089500006212,
     author = {Wohlfahrt, K.},
     title = {Macbeath's curve and the modular group},
     journal = {Glasgow mathematical journal},
     pages = {239--247},
     year = {1985},
     volume = {26},
     doi = {10.1017/S0017089500006212},
     url = {http://geodesic.mathdoc.fr/articles/10.1017/S0017089500006212/}
}