TY  - JOUR
AU  - S. Mrówka
TI  - On the potency of subsets of βN
JO  - Colloquium Mathematicum
PY  - 1959
SP  - 23
EP  - 25
VL  - 7
IS  - 1
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/articles/10.4064/cm-7-1-23-25/
DO  - 10.4064/cm-7-1-23-25
LA  - en
ID  - 10_4064_cm_7_1_23_25
ER  -