*[http://www.scientificamerican.com/article.cfm?id=snake-oil-salesmen-knew-something Snake Oil Salesmen Were on to Something; Scientific American 01.11.2007]
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*[http://www.scientificamerican.com/article.cfm?id=snake-oil-salesmen-knew-something Snake Oil Salesmen Were on to Something; Scientific American vom 01.11.2007]