Guerrieri R, Mencuccini M, Sheppard LJ, Saurer M, Perks MP, Levy P, Sutton MA, Borghetti M, Grace J. The legacy of enhanced N and S deposition as revealed by the combined analysis of ?13C, ?18O and ?15N in tree rings. Global Change Biology. 2011  ;17(5):1946-1962.

Guerrieri R, Mencuccini M, Sheppard LJ, Saurer M, Perks MP, Levy P, Sutton MA, Borghetti M, Grace J. The legacy of enhanced N and S deposition as revealed by thecombined analysis of delta 13C, delta 18O and delta 15N in treerings. Global Change Biology. 2011  ;17:1946?1962.