TY  - JOUR
AU  - Butkovičová, Eva
TI  - Ultrafilters without immediate predecessors in Rudin-Frolík order
JO  - Commentationes Mathematicae Universitatis Carolinae
PY  - 1982
SP  - 757
EP  - 766
VL  - 23
IS  - 4
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/CMUC_1982__23_4_a12/
LA  - en
ID  - CMUC_1982__23_4_a12
ER  -