@article{article4006121c,
title   = {Some applications of a Simons' type formula for complete spacelike submanifolds in a semi-Riemannian space form},
author = {Chaves, Rosa Maria dos Santos Barreiro and Sousa, Junior, Luiz Amancio},
year = {2007},
doi = {10.1016/j.difgeo.2007.02.008},
journal   = {Differential Geometry and Its Applications}
}