@article {30015,
	title = {Field studies of pine, spruce and aspen periodically subjected to sulphur gas emissions. In : Proceedings of First International Symposium on Acid Precipitation and the Forest Ecosystem},
	volume = {General Technical Report NE 23},
	year = {1975},
	institution = {USAD Forest Service },
	author = {Legge, Allan H. and Amundson, R. G. and Jaques, D. R. and Walker, R. B.}
}
