Warttig SL, Forshaw MJ, South J, White AK. New, normative, English-sample data for the Short Form Perceived Stress Scale (PSS-4). J Health Psychol. 2013 Dec;18(12):1617-28. doi: 10.1177/1359105313508346
Ruiz-Castell M, Carsin AE, Barbieri FL, Paco P, Gardon J, Sunyer J. Child patterns of growth delay and cognitive development in a Bolivian mining city. Am J Hum Biol. 2013 Jan;25(1):94-100. doi: 10.1002/ajhb.22346
Phanikumar CV, Maitra B. Willingness-to-pay and preference heterogeneity for rural bus attributes. J Transp Eng A-Syst. 2007 Jan;133(1).