@article {1329,
	title = {Natural vegetation responses to atmospheric nitrogen deposition - critical levels and loads of nitrogen for vegetation growing on contrasting native soils},
	year = {1997},
	institution = {University of Sheneld},
	address = {Sheneld},
	author = {Carroll, J.A. and Caporn, S.J.M. and Morecrof, M.D. and Lee, J.A. and Johnson, D. and Taylor, A. and Leake, J.R. and Campbell, C.D. and Cawley, L. and Lei, Y. and Read, D.J.}
}
@inbook {527,
	title = {Acid Rain and its Impact: The Critical Loads Debate},
	year = {1994},
	pages = {146-150},
	publisher = {Environmental Change Research Centre/ENSIS},
	organization = {Environmental Change Research Centre/ENSIS},
	chapter = {Critical loads of nitrogen for upland heather (Calluna vulgaris). },
	address = {London},
	author = {Caporn, S.J.M and Carroll, J. and Lei, Y. and Song, W. and Read, D.J. and Lee, J.A. and Battarbee, R.W. (Eds)}
}
