@article {1677,
	title = {Direct and indirect effects of nitrogen deposition on species composition change in calcareous grasslands},
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	year = {2010},
	pages = {1871-83},
	author = {Van Den Berg, L.J.L. and Vergeer, P. and Rich, T.C.G. and Smart, S.M. and Guest, D. and Ashmore, M.R.}
}
@article {1674,
	title = {Detecting the signal of atmospheric N  deposition in recent national-scale vegetation change across Britain},
	volume = {4},
	year = {2004},
	pages = {269{\textendash}278},
	author = {Smart, S.M. and Ashmore, M.R. and Hornung, M.}
}
