Variable Nitrogen Fixation in Wild Populus Doty, Sharon L. ; Sher, Andrew W. ; Fleck, Neil D. ; Khorasani, Mahsa ; Bumgarner, Roger E. ; Khan, Zareen ; Ko, Andrew W. K. ; Kim, Soo-Hyung ; DeLuca, Thomas H. Abstract Publication: PLoS ONE Pub Date: May 2016 DOI: 10.1371/journal.pone.0155979 Bibcode: 2016PLoSO..1155979D