Slow Passage through a Saddle-Center Bifurcation. - David C. Diminnie; Richard Haberman (J. Nonlinear Sci., 2000)

Action and Period of homoclinic and Periodic orbits for the Unfolding of a saddle-Center bifurcation. - David C. Diminnie; Richard Haberman (Int. J. Bifurc. Chaos, 2003)