1. The Cochrane Collaboration; Bahrain Branch; Box 25438 Awali Bahrain
2. Leiden University Medical Center; Department of Dermatology; PO Box 9600 B1-Q Leiden Netherlands 2300 RC
3. West China Hospital, Sichuan University; Department of Dermatology; No. 37, Guo Xue Xiang Chengdu Sichuan China 610041