http://www.pbonline.co.uk/external_wall_insulation.html
http://www.energysavingtrust.org.uk/Find-Energy-Saving-Trust-Recommended-Products/browse/insulation/external-wall-insulation/-/15
http://www.decc.gov.uk/en/content/cms/tackling/green_deal/green_deal.aspx
http://www.which.co.uk/energy/saving-money/guides/how-to-buy-wall-insulation/solid-wall-insulation/
http://www.edfenergy.com/products-services/for-your-home/energy-saving-advice/measures-external-wall-insulation.shtml
PB online 2012
