Necessity and sufficiency conditions for the absolute null controllability for Linear delay perturbations
We are inspired by the works of Chukwu , Eke , Schinterdorf and Barmish  to unveil necessary and sufficient conditions for the absolute null controllability of a linear delay perturbed system with zero in the domain of null controllability.
Journal of the Nigerian Association of Mathematical Physics Vol. 10 2006: pp. 549-552