@incollection{eprints656,
           title = {Variety and Irreversibility in Scientific and Technological Systems: the Evolution of an Industry Network},
          series = {Routledge Siena studies in political economy},
            year = {2001},
          volume = {2},
           pages = {216--239},
         address = {London},
          editor = {Antonio Nicita and Ugo Pagano},
       booktitle = {Antonio Nicita and Ugo Pagano (eds). The Evolution of Economic Diversity},
       publisher = {Routledge},
          author = {Fabio Pammolli and Luigi Orsenigo and Massimo Riccaboni},
             url = {http://eprints.imtlucca.it/656/}
}