?url_ver=Z39.88-2004&rft_id=10.1021%2Facs.est.6b00181&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.au=Zhang%2C+Y.&rft.aulast=Zhang&rft.aufirst=Y.&rft.issue=16&rft.volume=50&rft.date=August+2016&rft.issn=1520-5851&rft.atitle=A+Network+Flow+Analysis+of+the+Nitrogen+Metabolism+in+Beijing%2C+China&rft.title=Environmental+Science+%26+Technology&rft.pages=8558-8567&rft.genre=article