@article {223,
	title = {The effects of air-borne nitrogen pollutants on species diversity in natural and semi-natural European vegetation},
	journal = {Journal of Ecology},
	volume = {86},
	year = {1998},
	pages = {717-738},
	author = {Bobbink, R. and Hornung, M. and Roelofs, J.G.M.}
}
