Contribution to the characterization of the sphere in E 3 Karel Svoboda (1979) Archivum Mathematicum Similarity:
Remark on surfaces in E 4 satisfying certain relations between covariant derivatives of the mean and Gauss curvatures Karel Svoboda (1978) Commentationes Mathematicae Universitatis Carolinae Similarity:
Some global characterizations of the sphere in E 4 Karel Svoboda (1978) Časopis pro pěstování matematiky Similarity: