Homoclinic Phenomena for Orbits Doubly Asymptotic to an Invariant Three-Sphere Robert EastonRichard McGehee Indiana University Mathematics Journal 1979 text pdf 10.1512/iumj.1979.28.28015 10.1512/iumj.1979.28.28015 en Indiana Univ. Math. J. 28 (1979) 211 - 240 state-of-the-art mathematics http://iumj.org/access/