Fox, Carl Alan. 1980. ?The Effect Of Air Pollution On Western Larch As Detected By Tree-Ring Analysis?. Arizona State University. http://ezproxy.library.arizona.edu/login?url=http://proquest.umi.com/pqdweb?did=749712461&sid=13&Fmt=2&clientId=43922&RQT=309&VName=PQD.