1. The Sahlgrenska Academy at Göteborg University, Institute of Health and Care Sciences, Box 457, SE-405 30 Göteborg, Sweden
2. Johns Hopkins University School of Nursing, 525 N. Wolfe Street, Baltimore, MD 21205-2110, USA
3. Faculty of Education, Learning and Teaching Unit, Göteborg University, Box 300, SE-405 30 Göteborg, Sweden