Pages 26-27. US EPA: A Brief History of Acid Rain. United States EnvironmentalProtection Agency. 2002 [2010-11-18]. (原始内容存档于2010-09-25). 'Cap-and-trade'
quality simulation model for the Truckee River, Earth Metrics Inc., EnvironmentalProtection Agency Technology Series Washington D.C. (1987) Charles F Wilkinson
of the American Environmental Movement (2005) David Urbinato. London's Historic 'Pea-Soupers'. United States EnvironmentalProtection Agency. Summer 1994