TY  - JOUR
AU  - Andreas Blass
TI  - Two closed categories of filters
JO  - Fundamenta Mathematicae
PY  - 1977
SP  - 129
EP  - 143
VL  - 94
IS  - 2
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/articles/10.4064/fm-94-2-129-143/
DO  - 10.4064/fm-94-2-129-143
LA  - en
ID  - 10_4064_fm_94_2_129_143
ER  -