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
Bradley RH, National Institute of Child Health and Human Development (NICHD) Early Child Care Research Network, McLeod LD. Child care and common communicable illnesses in children aged 37 to 54 months. Arch Pediatr Adolesc. 2003 Feb;157(2):196-200. doi: 10.1001/archpedi.157.2.196
Clarkson TB, Anthony MS, Klein KP. Phytoestrogens: can hormone replacement be something you eat? Women's health digest. 1996;1(4):253-5.