Positive solutions of second-order singular boundary value problem with a Laplace-like operator. Ren, Jingli; Ge, Weigao — 2005 Journal of Inequalities and Applications [electronic only]
Existence and Lyapunov stability of periodic solutions for generalized higher-order neutral differential equations. Ren, Jingli; Cheung, Wing-Sum; Cheng, Zhibo — 2011 Boundary Value Problems [electronic only]