Periodic solutions of a periodic Lotka–Volterra system with delays

A Lotka–Volterra periodic delay model with <f>m</f>-predators and <f>n</f>-preys is studied in this paper. Sufficient conditions for the global existence of a positive periodic solutions of this delay model are obtained by means of topological degree. Finally, a suitable example is given to illustrate that the conditions of the main theorem are feasible. [Copyright &y& Elsevier]