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 A. Halanay , Differential Equations: Stability, Oscillations, Time Lags (Academic Press, New York, 1966).
 L. Hatvani , ‘On the uniform attractivity of solutions of ordinary differential equations by two Lyapunov functions’, Proc. Japan Acad. 67 (1991), 162–167.
 L. Hatvani , ‘On the asymptotic stability for a two-dimensional linear nonautonomous differential system’, Nonlinear Anal. 25 (1995), 991–1002.
 D. R. Merkin , Introduction to the Theory of Stability, Texts in Applied Mathematics, 24 (Springer, New York, 1997).
 N. Rouche , P. Habets and M. Laloy , Stability Theory by Liapunov’s Direct Method, Applied Mathematical Sciences, 22 (Springer, New York, 1977).
 A. Strauss and J. A. Yorke , ‘Perturbing uniformly stable linear systems with and without attraction’, SIAM J. Appl. Math. 17 (1969), 725–738.