TY  - JOUR
TI  - Announcement. Mathematica Bohemica
JO  - Mathematica Bohemica
PY  - 1991
VL  - 116
IS  - 1
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/articles/10.21136/MB.1991.116993/
DO  - 10.21136/MB.1991.116993
LA  - cz
ID  - 10_21136_MB_1991_116993
ER  -