@article{CMH_1974__49_139577,
     author = {D. de Werra},
     title = {Partitions of {Graphs} into {Coverings} and {Hypergraphs} into {Transversals}},
     journal = {Commentarii mathematici Helvetici},
     pages = {175--178},
     publisher = {mathdoc},
     volume = {49},
     year = {1974},
     zbl = {0284.05131},
     url = {http://geodesic.mathdoc.fr/item/CMH_1974__49_139577/}
}