@article{article9962212e,
title   = {Transformation of the nitrogen cycle: recent trends, questions, and potential solutions},
author = {Galloway, James Neville and Townsend, Alan R and Erisman, Jan Willem and Bekunda, Mateete and Cai, Zucong and Freney, John Raymond and Martinelli, Luiz Antonio and Seitzinger, Sybil P and Sutton, Mark A.},
year = {2008},
journal   = {Science}
}