Luciano JV, Barrada JR, Aguado J, Osma J, García-Campayo J. Bifactor analysis and construct validity of the HADS: a cross-sectional and longitudinal study in fibromyalgia patients. Psychological Assessment. 2014 Jun;26(2):395-406.
Evans MF, Poulos C, Smith VK. Who counts in evaluating the effects of air pollution policies on households? Non-market valuation in the presence of dependencies. J Environ Econ Manage. 2011 Jul 1;62(1):65-79.
Smith VK, Mansfield CA. Buying time: real and hypothetical offers. J Environ Econ Manage. 1998;36(3):209-24.
Glass RL, Rothman KJ, Espinal F, Velez H, Smith NJ. Prevalence of human dental caries and water-borne trace metals. Arch Oral Biol. 1973 Sep;18(9):1099-104. doi: 10.1016/0003-9969(73)90083-6