Mixed dynamics of 2-dimensional reversible maps with a symmetric couple   of quadratic homoclinic tangencies
  We study dynamics and bifurcations of 2-dimensional reversible maps having a symmetric saddle fixed point with an asymmetric pair of nontransversal homoclinic orbits (a symmetric nontransversal homoclinic figure-8). We consider one-parameter families of reversible maps unfolding the initial homoclinic tangency and prove the existence of infinitely many sequences (cascades) of bifurcations related to the birth of asymptotically stable, unstable and elliptic periodic orbits. 
A. Delshams, M.S. Gonchenko, S.V. Gonchenko, and J.T L\'azaro
math.DS