“…We must mention that several other approaches have been however discussed in the literature: see, for instance, the generalized Adams methods [10], extensions of the Runge-Kutta methods [11], generalized exponential integrators [12,13], spectral methods [14,15], spectral collocation methods [16], methods based on matrix functions [17][18][19][20], and so on. In this paper, for brevity, we focus only on PI rules and FLMMs, and we refer the reader to the existing literature for alternative approaches.…”