@article{ASENS_2007_4_40_6_845_0,
     author = {Morales-Ruiz, Juan J. and Ramis, Jean-Pierre and Sim\'o, Carles},
     title = {Integrability of hamiltonian systems and differential {Galois} groups of higher variational equations},
     journal = {Annales scientifiques de l'\'Ecole Normale Sup\'erieure},
     pages = {845--884},
     publisher = {Elsevier},
     volume = {Ser. 4, 40},
     number = {6},
     year = {2007},
     doi = {10.1016/j.ansens.2007.09.002},
     mrnumber = {2419851},
     zbl = {1144.37023},
     language = {en},
     url = {http://archive.numdam.org/articles/10.1016/j.ansens.2007.09.002/}
}