@article{AUCMP_1998__39_1-2_a11,
     author = {Simon, Petr},
     title = {A hedgehog in a product},
     journal = {Acta Universitatis Carolinae. Mathematica et Physica},
     pages = {147--153},
     publisher = {mathdoc},
     volume = {39},
     number = {1-2},
     year = {1998},
     mrnumber = {1696588},
     zbl = {1007.54023},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/AUCMP_1998__39_1-2_a11/}
}