1. Burgiel S, Foote G, Orellana M, Perrault A (2006) Invasive alien species and trade: integrating prevention measures and international trade rules. Defenders of wildlife. Center for International Environmental Law. The Nature Conservancy. 54 p.
http://www.cleantrade.net
. Accessed on 1 February 2008
2. CBD (2002) Sixth conference of the parties. The Hagues, the Netherlands, 7–19 April 2002: Decision VI/23: Alien species that threaten ecosystems, habitats or species to which is annexed guiding principles for the prevention, introduction and mitigation of impacts of alien species that threaten ecosystems, habitats or species. Available at
www.biodiv.org
3. CBD (2006) Alien species that threaten ecosystems, habitats or species (Article 8(h) ): Further consideration of gaps and inconsistencies in the international regulatory framework. (COP 8, Decision VIII/27).
http://www.cbd.int/decisions/cop-08.shtml?m=COP-08&id=11041&lg=0
. Accessed on 1 February 2008
4. Dawson FH, Warman EA (1987) Crassula helmsii(T. Kirk) cockayne: Is it an aggressive alien aquatic plant in Britain?. Biological Conservation 42, 247–272.
5. EPPO (1997) Decision-support scheme for quarantine pests. EPPO Standard PM 5/3 (2). Available at
www.eppo.org
. Accessed on 1 February 2008