@article {1574,
	title = {Long distance nitrogen air pollution effects on lichens in Europe.},
	journal = {Lichenologist},
	volume = {35},
	year = {2003},
	pages = {347-359},
	author = {Van Herk, C.M. and Mathijssen-Spiekman, E.A.M. and De Zwart, D.}
}
