Particulate air pollution and mortality in the United States: did the risks change from 1987 to 2000?
Dominici F, Peng RD, Zeger SL, White RH, Samet JM. Particulate air pollution and mortality in the United States: did the risks change from 1987 to 2000? Am J Epidemiol. 2007 Oct 15; 166(8):880-8.