@article {10403,
	title = {The Clean Air Challenge},
	journal = {National Parks},
	volume = {76},
	year = {2002},
	month = {November/December},
	pages = {16-17},
	keywords = {Acid rain, Air pollution, Climate change},
	url = {http://books.google.com/books?id=Oa_eVUD10MkC\&pg=PA16\&dq=national+parks+magazines\&source=gbs_toc_r\&cad=2$\#$v=onepage\&q\&f=false},
	author = {Jeffords, James M}
}
