1. Tufts Medical Center; Department of Pharmacy; 800 Washington St, Box 420 Boston USA
2. Cochrane; Cochrane Pain, Palliative and Supportive Care Review Group; Oxford Pain Research Churchill Hospital Oxford Oxfordshire UK OX3 7LE
3. Tufts Medical Center; Department of Anesthesiology; Boston Massachusetts USA
4. Tufts University School of Medicine; Pain Research, Education and Policy (PREP) Program, Department of Public Health and Community Medicine; Boston Massachusetts USA