@article{article50171bb7,
title   = {Permanence of stability for a class of system of differential equations with two delays},
author = {Aki, Sueli Mieko Tanaka and Godoy, Sandra Maria Semensato de},
year = {2009},
doi = {10.1016/j.nonrwa.2007.08.021},
journal   = {Nonlinear Analysis - Real World Applications}
}