@article {30669,
	title = {A lichen network as an early warning monitor of industry air emissions. In : Proceedings of Alberta Sulphur Gas Research Workshop III, Edmonton, Alberta, Nov. 17-18, 1977, edited by H. S. Sandhu and M. Nyborg},
	year = {1977},
	pages = {141-151},
	author = {Lulman, Philip D. and Peterson, Wilbur and Douglas, George W.}
}
