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.
Sturmer T, Joshi M, Glynn RJ, Avorn J, Rothman KJ, Schneeweiss S. A review of the application of propensity score methods yielded increasing use, advantages in specific settings, but not substantially different estimates compared with conventional multivariable methods. J Clin Epidemiol. 2006 May 1;59(5):437-47.