@article{10_21136_MB_1999_125973,
     author = {Zelinka, Bohdan},
     title = {A remark on graph operators},
     journal = {Mathematica Bohemica},
     pages = {83--85},
     year = {1999},
     volume = {124},
     number = {1},
     doi = {10.21136/MB.1999.125973},
     mrnumber = {1687488},
     zbl = {0933.05148},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.21136/MB.1999.125973/}
}