?url_ver=Z39.88-2004&rft_id=10.1002%2Fcplx.6130010109&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.au=Sigmund%2C+K.&rft.aulast=Sigmund&rft.aufirst=K.&rft.issue=1&rft.volume=1&rft.date=1995&rft.issn=1099-0526&rft.atitle=Darwin's+%22circles+of+complexity%22%3A+Assembling+ecological+communities&rft.title=Complexity&rft.pages=40-44&rft.genre=article