@article{CGTM_2009_2_a6,
     author = {Josep Freixas and Montserrat Pons},
     title = {Hierarchies in {Voting} {Simple} {Games}},
     journal = {Contributions to game theory and management},
     pages = {72--80},
     year = {2009},
     volume = {2},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/CGTM_2009_2_a6/}
}