@article{10_21136_CMJ_1959_100386,
     author = {Pt\'ak, Vlastimil},
     title = {A combinatorial theorem on systems of inequalities and its application to analysis},
     journal = {Czechoslovak Mathematical Journal},
     pages = {629--630},
     publisher = {mathdoc},
     volume = {09},
     number = {4},
     year = {1959},
     doi = {10.21136/CMJ.1959.100386},
     mrnumber = {0110007},
     zbl = {0093.05601},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.21136/CMJ.1959.100386/}
}