Herman's approach to quasi-periodic perturbations in the reversible KAM   context 2
  We revisit non-autonomous systems depending quasi-periodically in time within the reversible context 2 of KAM theory and obtain Whitney smooth families of invariant tori in such systems via Herman's method. The reversible KAM context 2 refers to the situation where the dimension of the fixed point manifold of the reversing involution is less than half the codimension of the invariant torus in question. 
Mikhail B. Sevryuk
math.DS