%0 Journal Article %A Kazuyuki Yagasaki %A Shogo Yamanaka %T Heteroclinic Orbits and Nonintegrability in Two-Degree-of-Freedom Hamiltonian Systems with Saddle-Centers %J Symmetry, integrability and geometry: methods and applications %D 2019 %V 15 %U http://geodesic.mathdoc.fr/item/SIGMA_2019_15_a48/ %G en %F SIGMA_2019_15_a48