Morozov, N. P. Periodic solutions of the equation \(\ddot x+\lambda f(ax+b\dot x)\dot x+x=0\). (Russian) Zbl 0625.34045 Differ. Uravn. 22, No. 5, 905-907 (1986). Reviewer: S.G.Hristova MSC: 34C25 PDFBibTeX XMLCite \textit{N. P. Morozov}, Differ. Uravn. 22, No. 5, 905--907 (1986; Zbl 0625.34045)
Gaponenko, Yu. L. On the question of boundedness of the solution of a second order linear equation. (Russian) Zbl 0613.34027 Differ. Uravn. 22, No. 5, 890-891 (1986). Reviewer: P.Moson MSC: 34C11 PDFBibTeX XMLCite \textit{Yu. L. Gaponenko}, Differ. Uravn. 22, No. 5, 890--891 (1986; Zbl 0613.34027)