“…The concept of stability for functional, differential, integral and integro-differential equations has been studied in a quite extensive way during the last six decades and have earned particular interest due to their great number of applications (see [1,3,5,6,8,9,10,11,12,13,14,15,16,18,19,20,21,22,23,26] and the references therein). This occurs with particular emphasis in the case of Hyers-Ulam and Hyers-Ulam-Rassias stabilities.…”