“…In the last fifty years, delay models are becoming more common, appearing in many branches of biological, economical and physical modelling (see [1]- [22], [24], [25]). This is due to their advantage of combining a simple, intuitive derivation with a wide variety of possible behavior regimes and to the fact that such models operate on an infinite dimensional space consisting of continuous functions that accommodate high dimensional dynamics (see [14], [20]- [21]).…”