1. Feedback invariants for nonlinear systems;Brockett,1978
2. A classification of linear controllable systems;Brunovsky;Kibernetika (Praha),1970
3. Control of nonlinear time-varying systems;Hunt,1981
4. Design for multi-input systems;Hunt,1983
5. Global transformations of nonlinear systems;Hunt;IEEE Trans Aut. Control,1983