1. European Portable Battery Association, 2006, http://www.epbaeurope.net.
2. European Battery Recycling Association, 2006, http://www.ebrarecycling.org.
3. European Union, 2006, http://europa.eu.int.
4. London Metal Exchange, 2006, http://www.lme.co.uk.
5. European Patent Office, 2006, http://www.european-patent-office.org.