TY  - JOUR
AU  - Thron, R.
AU  - Koppitz, J.
TI  - Free systems of algebras and ultraclosed classes.
JO  - Acta Mathematica Universitatis Comenianae. New Series
PY  - 2006
SP  - 127
VL  - 75
IS  - 1
PB  - mathdoc
UR  - https://geodesic-test.mathdoc.fr/item/AMUC2_2006__75_1_130057/
LA  - en
ID  - AMUC2_2006__75_1_130057
ER  -