1. United States Environmental Protection Agency 2008 http://www.epa.gov/ORD/NRMRL/lcaccess/pdfs/600r06060.pdf
2. Environmental Assessment of Products
3. International Organization of Standardization 2006
4. International Organization of Standardization 2006
5. Pré Consultants 2000 The Eco-indicator 99 - a damage oriented method for life cycle impact assessment -