[1] В. Y. Chen, L. Vanhecke:
Differential geometry of geodesic spheres. J. Reine Angew. Math. 325 (1981), 28-67.
MR 0618545 |
Zbl 0503.53013
[3] A. Gray, L. Vanhecke:
The volumes of tubes about curves in a Riemannian manifold. Proc. London Math. Soc. 44 (1982), 215-243.
MR 0647431 |
Zbl 0491.53035
[5] H. S. Ruse A. G. Walker, T. J. Willmore:
Harmonic Spaces. Cremonese, Roma, 1961.
MR 0142062