TY  - JOUR
TI  - [unknown]
JO  - Acta mathematica Universitatis Comenianae
PY  - 1987
SP  - 311
EP  - 318
VL  - 48-49
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/AMUC_1987__48-49_185952/
ID  - AMUC_1987__48-49_185952
ER  -