Fondell E, Lagerros YT, Sundberg CJ, Lekander M, Balter O, Rothman KJ, Balter K. Physical activity, stress, and self-reported upper respiratory tract infection. Med Sci Sports Exerc. 2011 Feb 1;43(2):272-9.
Mansfield CA, Johnson FR, Van Houtven GL. The missing piece: valuing averting behavior for children's ozone exposures. Resour Energy Econ. 2006 Aug;28(3):215-28.
Smith VK, Poulos C, Kim H. Treating open space as an urban amenity. Resour Energy Econ. 2002 Feb 15;24(1-2):107-29.