Gao, Bo; He, Zhirong Limit cycles of a class of planar system with \(1:2\) resonance for linear cusp. (Chinese. English summary) Zbl 1212.34101 J. Sichuan Univ., Nat. Sci. Ed. 46, No. 5, 1224-1228 (2009). MSC: 34C05 34C07 37G10 37G15 34C23 34C37 34E10 PDFBibTeX XMLCite \textit{B. Gao} and \textit{Z. He}, J. Sichuan Univ., Nat. Sci. Ed. 46, No. 5, 1224--1228 (2009; Zbl 1212.34101)
He, Zhirong; Zhang, Weinian Critical periods of a periodic annulus linking to equilibria at infinity in a cubic system. (English) Zbl 1180.34034 Discrete Contin. Dyn. Syst. 24, No. 3, 841-854 (2009). Reviewer: Valery A. Gaiko (Minsk) MSC: 34C08 37J45 34C05 PDFBibTeX XMLCite \textit{Z. He} and \textit{W. Zhang}, Discrete Contin. Dyn. Syst. 24, No. 3, 841--854 (2009; Zbl 1180.34034) Full Text: DOI