@article{GDZPPN002319551, title = {Jacobi Tensors and Ricci Curvature.}, journal = {Mathematische Annalen}, volume = {250}, year = {1980}, pages = {1-26}, zbl = {0423.53035}, url = {http://dml.mathdoc.fr/item/GDZPPN002319551} }
O'Sullivan, John J.; Eschenburg, Jost-Hinrich. Jacobi Tensors and Ricci Curvature.. Mathematische Annalen, Tome 250 (1980) pp. 1-26. http://gdmltest.u-ga.fr/item/GDZPPN002319551/