1. Stable systems of differential equations with integrable perturbation term;Antosiewicz, H. A.;J. London Math. Soc.,1956
2. Perturbations of nonlinear systems of differential equations. III;Brauer, Fred;J. Math. Anal. Appl.,1970
3. L. Cesari, Asymptotic behavior and stability problems in ordinary differential equations, Ergebnisse der Math. und ihrer Grenzgebiete, N. F., Band 16, Academic Press, New York; Springer-Verlag, Berlin, 1963. MR 27 #1661.
4. Asymptotic behavior for differential equations which cannot be locally linearized;Lasota, A.;J. Differential Equations,1971