1. New York City recycling update;Rockwell;BioCycle,1994
2. Urban Air Pollution in the Megacities of the World;United Nations Environment Program/World Health Organization,1992
3. Fuel cells: energy conversion for the next century;Kartha;Physics Today,1994
4. A Technical and Economic Assessment of Renewable Transportation Fuels and Technologies;Ogden,1994
5. H-Power to roll out commercial fuel cell busses next summer, seeks ZEV certificate;Hoffman;Hydrogen and Fuel Cell Letter,1995