참고문헌
- Trans. Amer. Math. Soc. v.145 Manifolds of negative curvature R. L. Bishop;B. O'Neill
- Sochow J. Math. v.5 Totally imbilical submanifolds B. Y. Chen
- Tensor N. S. v.7 On conharmonic transformation Y. Ishi
- Kyungpook Math. J. v.35 Warped products with critical Riemannian metrics Ⅱ I. B. Kim;B. H. Kim