long lasting:http://www.telegraph.co.uk/finance/property/green/9695896/Eco-living-The-mattresses-that-last-50-years.html
arthritis etc:http://www.organic.org/articles/showarticle/article-204
Synthetics vs. natural materials: http://www.motherjones.com/politics/2008/03/should-you-ditch-your-chemical-mattress