@article{GDZPPN002222787,
title = {Line Integration of Ricci Curvature and Conjugate Points in Lorentzian and Riemannian Manifolds.},
journal = {Manuscripta mathematica},
volume = {31},
year = {1980},
pages = {297-316},
zbl = {0436.53043},
url = {http://dml.mathdoc.fr/item/GDZPPN002222787}
}
Ehrlich, P.; Chicone, Carmen. Line Integration of Ricci Curvature and Conjugate Points in Lorentzian and Riemannian Manifolds.. Manuscripta mathematica, Tome 31 (1980) pp. 297-316. http://gdmltest.u-ga.fr/item/GDZPPN002222787/