@article{CMUC_1985__26_2_a13, author = {\'Ulehla, Josef}, title = {On racial insufficiency: {White} messengers cannot simulate coloured ones}, journal = {Commentationes Mathematicae Universitatis Carolinae}, pages = {323--325}, publisher = {mathdoc}, volume = {26}, number = {2}, year = {1985}, mrnumber = {803930}, zbl = {0568.68033}, language = {en}, url = {http://geodesic.mathdoc.fr/item/CMUC_1985__26_2_a13/} }