@article{article563ce902,
title   = {Spectral flow, Maslov index and bifurcation of semi-Riemannian geodesics},
author = {Piccione, Paolo and Portaluri, Alessandro and Tausk, Daniel Victor},
year = {2004},
doi = {10.1023/B:AGAG.0000018558.65790.db},
journal   = {Annals of Global Analysis and Geometry}
}