Hall RJ, Emmett B, Garbutt A, Jones L, Rowe E, Sheppard L, Vanguelova E, Pitman R, Britton A, Hester A, et al. UK Status Report July 2011: Update to empirical critical loads of nitrogen.; 2011 p. 55pp.

Bobbink R, Hicks K, Galloway J, Spranger T, Alkemade R, Ashmore M, Bustamante M, Cinderby S, Davidson E, Dentener F, et al. Global assessment of nitrogen deposition effects on terrestrial plant diversity: a synthesis. Ecological Applications. 2010  ;20(1):30-59.