?url_ver=Z39.88-2004&rft_id=10.1103%2FPhysRevE.70.027102&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.aulast=Caldarelli&rft.au=Caldarelli%2C+Guido&rft.aufirst=Guido&rft.date=2004&rft.issue=2&rft.volume=70&rft.title=Physical+Review+E&rft.atitle=Preferential+exchange%3A+strengthening+connections+in+complex+networks&rft.issn=1539-3755&rft.genre=article