@article{10_21136_CMJ_1987_102157,
     author = {Zelinka, Bohdan},
     title = {Tolerances on graph algebras},
     journal = {Czechoslovak Mathematical Journal},
     pages = {313--317},
     publisher = {mathdoc},
     volume = {37},
     number = {2},
     year = {1987},
     doi = {10.21136/CMJ.1987.102157},
     mrnumber = {882602},
     zbl = {0623.05022},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.21136/CMJ.1987.102157/}
}