1. Stability and Asymptotic Behavior of Differential Equations;Coppel,1965
2. Fixed Point Theorems;Smart,1974
3. Disconjugacy;Coppel,1971
4. Disconjugacy and Wronskians;Hartman,1971
5. Problemi ai limiti lineari generali per i sistemi di equazioni differenzialai ordinarie;Conti;Boll. Un. mat. Ital.,1953