@article{SigmanDiFioreHainetal.2009,
  author    = {Daniel M. Sigman and Peter J. DiFiore and Mathis P. Hain and Curtis Deutsch and Yi Wang and David M. Karl and Angela N. Knapp and Moritz F. Lehmann and Silvio Pantoja},
  title     = {The dual isotopes of deep nitrate as a constraint on the cycle and budget of oceanic fixed nitrogen},
  doi       = {10.1016/j.dsr.2009.04.007},
  url       = {http://www.sciencedirect.com/science/journal/09670637},
  year      = {2009},
}