Hui, Jing et Chen, Lan Sun, Existence of Positive Periodic Solution of Periodic Time-Dependent Predator-Prey System with Impulsive Effects, Acta mathematica Sinica. English series (Print) , 20(3), 2004, pp. 423-432
The general system of differential equations describing predator-prey dynamics with impulsive effects is modified by the assumption that the coefficients are periodic functions of time. By use of standard techniques of bifurcation theory, it is known that this system has a positive periodic solution provided the time average of the predators net uninhibited death rate is in a suitable range. The bifurcation is from the periodic solution of the time-dependent logistic equation for the prey (which results in the absence of predator).