Helmi
Curt Trennepohl
Soňa Košičiarová
United States. General Accounting Office
Instituto Brasileiro do Meio Ambiente e dos Recursos Naturais Renováveis
A. Roger Greenway
J. Struiksma
Melissa Malkin
Francisco Cholbi Cachá
J. E. Hoitink
Maine. Dept. of Environmental Protection.
Massachusetts. Dept. of Environmental Quality Engineering.
P. Houweling
Marc Pirlet
D. van der Meijden
Unknown Author
Arizona. Department of Environmental Quality
Virginia. Department of Environmental Quality