@article{MS2_1960__8_165747,
     author = {B. Gr\"unbaum and E. Asplund},
     title = {On a {Coloring} {Problem.}},
     journal = {Mathematica Scandinavica},
     pages = {181--188},
     publisher = {mathdoc},
     volume = {8},
     year = {1960},
     zbl = {0095.17002},
     url = {http://geodesic.mathdoc.fr/item/MS2_1960__8_165747/}
}