Artés, Joan C.; Llibre, Jaume; Schlomiuk, Dana The geometry of quadratic polynomial differential systems with a weak focus and an invariant straight line. (English) Zbl 1208.34035 Int. J. Bifurcation Chaos Appl. Sci. Eng. 20, No. 11, 3627-3662 (2010). MSC: 34C05 34C23 34C45 PDFBibTeX XMLCite \textit{J. C. Artés} et al., Int. J. Bifurcation Chaos Appl. Sci. Eng. 20, No. 11, 3627--3662 (2010; Zbl 1208.34035) Full Text: DOI
Artés, Joan C.; Llibre, Jaume; Schlomiuk, Dana The geometry of quadratic differential systems with a weak focus of second order. (English) Zbl 1124.34014 Int. J. Bifurcation Chaos Appl. Sci. Eng. 16, No. 11, 3127-3194 (2006). Reviewer: Valery A. Gaiko (Minsk) MSC: 34C05 37G10 37G15 34C23 PDFBibTeX XMLCite \textit{J. C. Artés} et al., Int. J. Bifurcation Chaos Appl. Sci. Eng. 16, No. 11, 3127--3194 (2006; Zbl 1124.34014) Full Text: DOI