1. On certain cases of dependence of the periodic motions of a relay system on parameters;Brusin,1963
2. On approximations and the coarseness of the parameter space of a dynamic system;Bautin;PMM,1969
3. Nonlinear Oscillations in Physical Systems;Hayashi,1964
4. Behavior of Dynamic Systems Near the Boundaries of a Stability Domain;Bautin,1949
5. The method of point mappings in the theory of nonlinear oscillations;Neimark,1958