TY  - JOUR
AU  - Biryukov, Petr A.
TI  - Cardinalities and ranks of $\pi$-bases in topological spaces
JO  - Commentationes Mathematicae Universitatis Carolinae
PY  - 1980
SP  - 769
EP  - 776
VL  - 21
IS  - 4
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/CMUC_1980__21_4_a12/
LA  - en
ID  - CMUC_1980__21_4_a12
ER  -