1. http://www.europa.eu.int/comm/environment/ipp/integratedpp.htm
2. http://europa.eu.int/comm/enterprise/chemicals/sustdev/pvc_en.htm
3. http://www.un.org/esa/sustdev/documents/docs_unced.htm
4. http://unfccc.int/essential_background/kyoto_protocol/items/2830.php
5. http://www.bmu.de/klimaschutz/downloads/doc/35742.php