1. Iberoamerican Cochrane Centre; Hospital de la Santa Creu i Sant Pau Sant Antoni Maria Claret 171 (Casa de Convalescencia) Barcelona Spain 08041
2. McMaster University; Health Sciences Centre; 1200 Main Street West Room 2C12 Hamilton Ontario Canada L8N 3Z5
3. McMaster University; Department of Clinical Epidemiology and Biostatistics; Hamilton ON Canada L8N
4. University of Illinois; College of Medicine; 401 Roxbury Road Rockford Illinois USA 61107
5. Instituto Universitario Dexeus; Obstetrics and Gynaecology; C/ del Pi 16 2º 1ª Barcelona Spain 08002
6. Canadian College of Naturopathic Medicine; 1255 Sheppard Ave. East North York Ontario Canada M2K 1E2
7. Sichuan University; West China Hospital; No. 37, Guo Xue Xiang Chengdu Sichuan China 610041