Jx. Xu et Q. Zheng, ON THE REDUCIBILITY OF LINEAR-DIFFERENTIAL EQUATIONS WITH QUASI-PERIODIC COEFFICIENTS WHICH ARE DEGENERATE, Proceedings of the American Mathematical Society, 126(5), 1998, pp. 1445-1451
This paper proves the reducibility of a class of linear differential e
quations with quasiperiodic coefficients which are degenerate with res
pect to a small perturbation parameter. Our results generalize some th
at were obtained by Jorba and Simo.