Please, when you use Imita.db cite as follows:

When using the data: Imita.db, http://imitadb.unisi.it

When referring to underlying methodology: Vasta, M. (2006), “Appendix: the source and the Imita.db dataset”, in R. Giannetti, M. Vasta (eds), Evolution of Italian Enterprises in the 20th Century, Heidelberg-New York, Physica-Verlag (Springer), pp. 269-273.