@article{10_21136_CPM_1987_108565,
     author = {Zelinka, Bohdan},
     title = {Distances between directed graphs},
     journal = {\v{C}asopis pro p\v{e}stov\'an{\'\i} matematiky},
     pages = {359--367},
     publisher = {mathdoc},
     volume = {112},
     number = {4},
     year = {1987},
     doi = {10.21136/CPM.1987.108565},
     mrnumber = {921325},
     zbl = {0643.05033},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.21136/CPM.1987.108565/}
}