1. Environmental Protection Agency 2006 http://www.epa.gov/ncea/pdfs/Ozone/Vol1fm.pdf
2. Government of British Columbia, Ministry of Environment 2007 http://wlapwww.gov.bc.ca/sry/p2/air_quality/index.html
3. Physical-statistical modeling in geophysics;Berliner;Journal of Geophysical Research,2003