TY  - JOUR
AU  - Svoboda, Karel
TI  - Several new characterizations of the 2-dimensional sphere in $E^4$
JO  - Czechoslovak Mathematical Journal
PY  - 1979
SP  - 573
EP  - 583
VL  - 29
IS  - 4
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/articles/10.21136/CMJ.1979.101639/
DO  - 10.21136/CMJ.1979.101639
LA  - en
ID  - 10_21136_CMJ_1979_101639
ER  -