Acknowledgments
We are deeply grateful to the Associate Editor, Prof. Emilio Galán, for
his detailed reviewof thismanuscript, improving it bymeans of several
comments and suggestions, and for his editorial handling of the paper.
Two anonymous reviewers are acknowledged for their suggestions on
an earlier version of the manuscript. Thanks are also due to Antoine
vanMaarle for his help in revising the English style. MM acknowledges
the research grants from University of Urbino (RicSci DiSTeVA 2014)
“Carlo Bo” (DiSTeVA 2014).