Dai, Guo Ren; Xu, Chang Xing Predator-prey systems with a constant harvesting rate of the predator population and with Holling type I functional response. (Chinese) Zbl 0900.92146 Acta Math. Sci. (Chin. Ed.) 14, No. 2, 134-144 (1994). Cited in 1 Document MSC: 92D40 Ecology 34C05 Topological structure of integral curves, singular points, limit cycles of ordinary differential equations PDFBibTeX XMLCite \textit{G. R. Dai} and \textit{C. X. Xu}, Acta Math. Sci. (Chin. Ed.) 14, No. 2, 134--144 (1994; Zbl 0900.92146)