@article{10_4064_aa166_4_5,
     author = {Jacek Pomyka{\l}a},
     title = {On $q$-orders in primitive modular groups},
     journal = {Acta Arithmetica},
     pages = {397--404},
     publisher = {mathdoc},
     volume = {166},
     number = {4},
     year = {2014},
     doi = {10.4064/aa166-4-5},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.4064/aa166-4-5/}
}