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
Strickland A, Brogan AJ, Krauss J, Martindale R, Cresci G. Is the use of specialized nutritional formulations a cost-effective strategy? A national database evaluation. J Parenter Enter Nutr. 2005 Jan 1;29(1 Suppl):S81-91.