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	title = {Interpreting nitrogen pollution thresholds for sensitive habitats: The importance of concentration versus dose},
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	volume = {152},
	year = {2008},
	pages = {253-256},
	author = {Pearce, I. and Van der Wal, R.}
}
@article {1358,
	title = {Interplay between nitrogen deposition and grazing causes habitat degradation},
	journal = {Ecology Letters},
	volume = {6},
	year = {2003},
	pages = {141-146},
	author = {Van der Wal, R. and Pearce, I. and Brooker, R. and Scott, D. and Welch, D. and Woodin, S.}
}
