@article {29474,
	title = {The use of lichens as bio-indicators of sulphur dioxide. In : Proceedings of a workshop on sulphur gas research in Alberta, Drake Hocking and David Reiter, editors},
	volume = {Information Report NOR-X-72},
	year = {1973},
	pages = {120-128},
	institution = {Alberta Environment, Research Secretariat, Environment Canada, Northern Forest Research Centre},
	address = {Edmonton, AB},
	author = {Case, J. W.}
}
