@article {Chen2005,
 author="Bang-Yen Chen",
 title={Examples and classification of Riemannian submersions satisfying a basic equality},
 journal="Bull. Austral. Math. Soc.",
 fjournal={Bulletin of the Australian Mathematical Society},
 volume="72",
 year="2005",
 number="3",
 pages="391--402",
 issn="0004-9727",
 coden="ALNBAB",
 language="English",
 date="4th July, 2005",
 classmath="53C40, 53C42, 53B25",
 publisher={AMPAI, Australian Mathematical Society},
 url="http://www.austms.org.au/Publ/Bulletin/V72P3/723-5198-Chen/index.shtml",
 acknowledgement={},
 abstract={ In an earlier article we obtain a sharp inequality for an arbitrary isometric immersion from a Riemannian manifold admitting a Riemannian submersion with totally geodesic fibres into a unit sphere. In this article we investigate the immersions which satisfy the equality case of the inequality. As a by-product, we discover a new characterisation of Cartan hypersurface in $S^4$. }
}