Existence and Stability of Almost Periodic Solutions of Differential   Equations with Generalized Piecewise Constant Argument
  This work deals with the existence of an almost periodic solution for certain kind of differential equations with generalized piecewise constant argument, almost periodic coefficients which are seen as a perturbation of a linear equation of that kind satisfying an exponential dichotomy on a difference equation. The stability of that solution in a semi-axis studied. 
Samuel Castillo and Manuel Pinto
math.DS