?url_ver=Z39.88-2004&rft_id=10.1103%2FPhysRevLett.76.4983&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.aufirst=Guido&rft.aulast=Caldarelli&rft.au=Caldarelli%2C+Guido&rft.date=June+1996&rft.title=Physical+Review+Letters&rft.atitle=Branching+processes+and+evolution+at+the+ends+of+a+food+chain&rft.issue=26&rft.pages=4983-4986&rft.volume=76&rft.issn=0031-9007&rft.genre=article