“…To obtain an alternative integral representation for G(t), which generalises (9), we use the relation of this function and the solution of a relaxation equation with a general fractional Caputo derivative with kernel k(t), and we apply the subordination principle for this equation [16,23,24]. The concept of subordination, originally introduced by Bochner in the theory of stochastic processes, has developed recently into a powerful tool in the study of anomalous relaxation and diffusion processes and the physics of complex systems (see, e.g., [25][26][27] and the recent review paper [28]).…”