@article{10_4064_cm_7_1_23_25,
     author = {S. Mr\'owka},
     title = {On the potency of subsets of {\ensuremath{\beta}N}},
     journal = {Colloquium Mathematicum},
     pages = {23--25},
     publisher = {mathdoc},
     volume = {7},
     number = {1},
     year = {1959},
     doi = {10.4064/cm-7-1-23-25},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.4064/cm-7-1-23-25/}
}