@article{ARM_1977__13_2_a6,
     author = {Sap\'ak, Old\v{r}ich},
     title = {Representation of the finite directed acyclic graph},
     journal = {Archivum mathematicum},
     pages = {111--116},
     publisher = {mathdoc},
     volume = {13},
     number = {2},
     year = {1977},
     mrnumber = {0485517},
     zbl = {0373.05041},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/ARM_1977__13_2_a6/}
}