@article{10_21136_CMJ_1978_101544,
     author = {Zelinka, Bohdan},
     title = {Derivatives of hypergraphs},
     journal = {Czechoslovak Mathematical Journal},
     pages = {394--399},
     publisher = {mathdoc},
     volume = {28},
     number = {3},
     year = {1978},
     doi = {10.21136/CMJ.1978.101544},
     mrnumber = {501206},
     zbl = {0444.05059},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.21136/CMJ.1978.101544/}
}