@article{CMH_1972__47_139515,
     author = {Friedrich Wille},
     title = {\"Uberdeckungen mit konvexen {Mengen} und nichtlineare {Gleichungssyteme}},
     journal = {Commentarii mathematici Helvetici},
     pages = {273--288},
     publisher = {mathdoc},
     volume = {47},
     year = {1972},
     zbl = {0251.52023},
     url = {http://geodesic.mathdoc.fr/item/CMH_1972__47_139515/}
}