1. Western Norway University of Applied Sciences; Faculty of Health and Social Sciences; Bergen Norway
2. Norwegian Institute of Public Health; Division for Health Services; PO Box 4404 Nydalen Oslo Norway 0403
3. University College of Southeast Norway; Faculty of Health and Social Sciences; Oslo Norway
4. Oslo and Akershus University College; Faculty of Health Sciences; PB4 St.Olavs plass Oslo Norway N-0130