@article{10_21136_CMJ_1984_101972,
     author = {Je\v{z}ek, Jaroslav and Kepka, Tom\'a\v{s}},
     title = {Modular groupoids},
     journal = {Czechoslovak Mathematical Journal},
     pages = {477--487},
     publisher = {mathdoc},
     volume = {34},
     number = {3},
     year = {1984},
     doi = {10.21136/CMJ.1984.101972},
     mrnumber = {761429},
     zbl = {0571.20053},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.21136/CMJ.1984.101972/}
}