Chang, Xiaoyuan, and Junjie Wei. “Hopf Bifurcation and Optimal Control in a Diffusive Predator-Prey System With Time Delay and Prey Harvesting”. Nonlinear Analysis: Modelling and Control, vol. 17, no. 4, Oct. 2012, pp. 379-0, https://doi.org/10.15388/NA.17.4.14046.