1. Coexistence of competing predators in a chemostat;Butler;J Math Biol,1983
2. Coincidence degree and nonlinear differential equations;Gaines,1977
3. The struggle for existence;Gause,1971
4. Stability and oscillation in delay differential equation of population dynamics;Gopalsamy,1992
5. Persistence for nonautonomous competition system with functional response;Gui;J Math Technol,2001