%0 Journal Article %A Zelinka, Bohdan %T Derivatives of hypergraphs %J Czechoslovak Mathematical Journal %D 1978 %P 394-399 %V 28 %N 3 %I mathdoc %U http://geodesic.mathdoc.fr/articles/10.21136/CMJ.1978.101544/ %R 10.21136/CMJ.1978.101544 %G en %F 10_21136_CMJ_1978_101544