@article{GDZPPN002236281,
title = {Bifurcation near solutions of variational problems with degenerate second variation.},
journal = {Manuscripta mathematica},
volume = {86},
year = {1995},
pages = {1-14},
zbl = {0816.58011},
url = {http://dml.mathdoc.fr/item/GDZPPN002236281}
}
Li-Jost, Xianqing. Bifurcation near solutions of variational problems with degenerate second variation.. Manuscripta mathematica, Tome 86 (1995) pp. 1-14. http://gdmltest.u-ga.fr/item/GDZPPN002236281/