@article{AIHPC_2008__25_3_539_0,
     author = {Barutello, Vivina and Secchi, Simone},
     title = {Morse index properties of colliding solutions to the $N$-body problem},
     journal = {Annales de l'I.H.P. Analyse non lin\'eaire},
     pages = {539--565},
     publisher = {Elsevier},
     volume = {25},
     number = {3},
     year = {2008},
     doi = {10.1016/j.anihpc.2007.02.005},
     zbl = {1143.70006},
     language = {en},
     url = {http://archive.numdam.org/articles/10.1016/j.anihpc.2007.02.005/}
}