@article {18, title = {Regional mass budgets of oxidized and reduced nitrogen and their relative contribution to the N inputs of sensitive ecosystems}, journal = {Environmental Pollutution (Nitrogen Conference Special Issue)}, volume = {102}, year = {1998}, pages = {337-342}, chapter = {1}, author = {Fowler, D. and Sutton, M.A. and Smith, R.I. and Pitcairn, C.E.R. and Coyle, M. and Campbel,l G. and Stedman, J.} }