1. Systematic reviews: critical links in the great chain of evidence;Mulrow,1998
2. Evidence based medicine: what it is and what it isn’t;Sackett;BMJ,1996
3. Information excess in medicine: overview, relevance to dermatology, and strategies for coping;Arndt;Arch Dermatol,1992
4. Principles of and procedures for systematic reviews;Egger,2001