1. V. M. Evtukhov and V. A. Kas’yanova, “Asymptotic behavior of unbounded solutions of essentially nonlinear second-order differential equations. I,” Ukr. Mat. Zh., 57, No. 3, 338–355 (2005).
2. V. P. Demidovich, Lectures on Mathematical Theory of Stability [in Russian], Nauka, Moscow (1967).
3. V. M. Evtukhov, “On solutions of real nonautonomous systems of quasilinear differential equations that vanish at infinity,” Differents. Uravn., 39, No. 4, 433–444 (2003).
4. E. Seneta, Regularly Varying Functions [Russian translation], Nauka, Moscow (1985).