1. Ministry of Health, Bahrain; UKCC (Bahrain Branch); Box 25438 Awali Bahrain
2. Clinical Trials & Epidemiology Research Unit; Singapore Branch, Australasian Cochrane Centre; Blk B #03-02 226 Outram Road Singapore Singapore 169039
3. University College London (UCL); Department of Epidemiology & Public Health; 1-19 Torrington Place London UK WC1E 6BT
4. Institute for Quality and Efficiency in Health care; Department of Health Information; Dillenburger Street 27, D-51105 Köln Germany D-51105
5. GKT Dental Institute King's College Hospital; Department of Oral Health Services Research & Dental Public Health; Denmark Hill Campus Caldecot Road London UK SE5 9RW