Yang, Jihua; Zhang, Erli; Liu, Mei The cyclicity of period annuli of a class of quartic Hamiltonian systems. (Chinese. English summary) Zbl 1389.37038 Adv. Math., Beijing 46, No. 2, 243-251 (2017). MSC: 37J45 34C05 34C07 34D10 PDFBibTeX XMLCite \textit{J. Yang} et al., Adv. Math., Beijing 46, No. 2, 243--251 (2017; Zbl 1389.37038)
Zhang, Zhifen; Li, Chengzhi On the number of limit cycles of a class of quadratic Hamiltonian systems under quadratic perturbations. (English) Zbl 0948.34020 Adv. Math., Beijing 26, No. 5, 445-460 (1997). Reviewer: Dmitry Turaev (Berlin) MSC: 34C07 37G15 34C23 PDFBibTeX XMLCite \textit{Z. Zhang} and \textit{C. Li}, Adv. Math., Beijing 26, No. 5, 445--460 (1997; Zbl 0948.34020)