@article{10_21136_CMJ_1983_101906,
     author = {Leutola, K. and Nieminen, J.},
     title = {Relations, coverings, hypergraphs and matroids},
     journal = {Czechoslovak Mathematical Journal},
     pages = {509--518},
     year = {1983},
     volume = {33},
     number = {4},
     doi = {10.21136/CMJ.1983.101906},
     mrnumber = {721080},
     zbl = {0539.08002},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.21136/CMJ.1983.101906/}
}