TY  - JOUR
AU  - H. Pawlak
AU  - R. Pawlak
TI  - On some properties of closed functions in terms of their levels
JO  - Commentationes Mathematicae
PY  - 1986
SP  -  81
EP  - 87
VL  - 26
IS  - 1
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/articles/10.14708/cm.v26i1.6154/
DO  - 10.14708/cm.v26i1.6154
LA  - pl
ID  - 10_14708_cm_v26i1_6154
ER  -