1. Observations on social capital;Arrow,1999
2. Baracchi, M., Bigarelli, D., 2001. Osservatorio sul settore biomedicale nel distretto mirandolese, Seconda rilevazione, Ricerche e Interventi di politica industriale e del lavoro (R&I), Carpi.
3. R&D cooperation and innovation activities of firms. Evidence for the German manufacturing industry;Becker;Research Policy,2004
4. Intangible assets: computers and organizational capital;Brynjolfsson;Brookings Papers on Economic Activity: Macroeconomics,2002
5. The evolution of industrial districts in Emilia Romagna;Brusco,1996