@article{10_1017_S0017089500006996,
     author = {Cori, R. and Machi', A.},
     title = {Flows on hypermaps},
     journal = {Glasgow mathematical journal},
     pages = {17--29},
     year = {1988},
     volume = {30},
     number = {1},
     doi = {10.1017/S0017089500006996},
     url = {http://geodesic.mathdoc.fr/articles/10.1017/S0017089500006996/}
}