Dynamics of an HBV/HCV infection model with intracellular delay and cell proliferation. - Zhang, Fengqin; Li, Jianquan; Zheng, Chongwu; Wang, Lin (Commun. Nonlinear Sci. Numer. Simul., 2017)

Positive periodic solutions for the neutral ratio-dependent predator-prey model. - Zhang, Fengqin; Zheng, Chongwu (Comput. Math. Appl., 2011)