@article {819,
	title = {Undergrowth as a biomonitor for deposition of N and acidity in pine forest.},
	journal = {Forest Ecology and Management },
	volume = {114},
	year = {1999},
	pages = {83-95},
	author = {Van Dobben, H.J. and Ter Braak, C.J.F. and Dirske, G.M.}
}
@article {548,
	title = {Effects of fertiliser on bryophytes in Swedish experiments on forest fertilisation.},
	journal = {Biological Conservation},
	volume = {59},
	year = {1992},
	pages = {155-161},
	author = {Dirske, G.M. and Martakis, G.F.P.}
}
