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
Vallano A, Mendoza G, Rodríguez A, Rebordosa C. Seguridad de los analgesicos y de los antiinflamatorios. Farm Hosp. 2004;157:23-31.