Girardot, Steven P., Barry P. Ryan, Susan M. Smith, Wayne T. Davis, Charles B. Hamilton, Richard A. Obenour, James R. Renfro, Kimberly A. Tromatore, and Gregory D. Reed. "Ozone and PM2.5 Exposure and Acute Pulmonary Health Effects: A Study of Hikers in the Great Smoky Mountains National Park." Environmental Health Perspectives 114, no. 7 (2006): 1044-1052.

Girardot, Steven P., Kimberly A. Tromatore, Yun F. Lam, Ryan W. Malone, Cynthia A. Atterholt, Wayne T. Davis, Charles B. Hamilton, James R. Renfro, Barry P. Ryan, Susan M. Smith et al. "Preliminary Findings From the Great Smoky Mountains National Park Air Quality and Hiker Health Study." Epidemiology 15, no. 4 (2004): S216.