Positive periodic solutions for a neutral delay ratio-dependent predatorprey model with a Holling type II functional response, Nonlinear Anal.RWA

By using a continuation theorem based on coincidence degree theory, we establish some easily verifiable criteria for the existence of positive periodic solutions for neutral delay ratio-dependent predator-prey model with Holling-Tanner functional response x t x t r t − a t x t − σ t − b t x t − σ t − c t x t y t / h t y t x t , y t y t d t − f t y t − τ t /x t − τ t