“…For further information concerning such classes of semigroups, we refer to [1]- [9], [13]- [14], [23]- [35], [47]- [51], and especially, to the monographs [3], [13], [38] and [54] where the interested reader can also find the basic material related to vector-valued Laplace transforms, degenerate semigroups, regularization methods and their importance in the theory of (higher-order) abstract Cauchy problems.…”