@article {1649,
	title = {The yield of winter cereals exposed to sulphur dioxide under field conditions.},
	journal = {Agriculture, Ecosystems and Environment},
	volume = {33},
	year = {1991},
	pages = {193-213},
	author = {McLeod, A.R. and Roberts, T.M. and Alexander, K. and Cribb, D.M.}
}
@article {764,
	title = {The effects of ozone and acid mist on Scots pine seedlings. },
	journal = {Oecologia},
	volume = {65},
	year = {1985},
	pages = {201},
	author = {Skeffington, R.A. and Roberts, T.M.}
}
