Mechanisms of Symmetry Creation
M. Dellnitz, M. Golubitsky, I. Melbourne, in: Bifurcation and Symmetry, Basel, 1992.

Generic Bifurcations of Pendula
M. Dellnitz, J.E. Marsden, I. Melbourne, J. Scheurle, in: Bifurcation and Symmetry, Basel, 1992.