1. ISO 14040.1 Committee Draft. Environmental Management–Life Cycle Assessment–Principles and Framework. 4/15/2004, Ref. no. ISO/TC 207/SC 5 N216 Rev. 01:04, 15 April 2004.
2. Tellus. Tellus Packaging Study. Tellus Institute: Boston, MA, 1992.
3. Estimated by Dr Roberta Cook, UC Davis, based on numerous public sources, including USDA, DOC and the 2002 US Economic Census.
4. http://www.pma.com [accessed 5 August 2005].