1. Asymptotic Behavior and Stability Problems in Ordinary Differential Equations;Cesari,1963
2. Fixed Points and Topological Degree in Nonlinear Analysis;Cronin,1964
3. Some periodic solutions of a four-body problem;Cronin;Icarus,1964
4. Oscillations in Nonlinear Systems;Hale,1963
5. Differential Equations: Geometric Theory;Lefschetz,1959