1. Environmental Governance: The Global Challenge;Hempel,1996
2. Earth in the Balance: Ecology and the Human Spirit;Gore,1992
3. quoting UN's 1996 World Population Prospects;USA TODAY,1997
4. Materials in a Steady State World;Brooks;Met. Trans.,1972
5. Strategy for Energy Conservation through Tribology;ASME Research Committee on Lubrication,1981