@article{ZNSL_2003_300_a9,
     author = {A. Delshams and P. Guti\'errez},
     title = {Exponentially small splitting of separatrices for whiskered tori in {Hamiltonian} systems},
     journal = {Zapiski Nauchnykh Seminarov POMI},
     pages = {87--121},
     publisher = {mathdoc},
     volume = {300},
     year = {2003},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/ZNSL_2003_300_a9/}
}