%0 Journal Article %A Svoboda, Karel %T Characterizations of the sphere in $E^4$ by means of the pseudoparallel mean curvature vector field %J Časopis pro pěstování matematiky %D 1980 %P 266-277 %V 105 %N 3 %I mathdoc %U http://geodesic.mathdoc.fr/articles/10.21136/CPM.1980.118069/ %R 10.21136/CPM.1980.118069 %G en %F 10_21136_CPM_1980_118069