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2. IEA Bioenergy Task 40 (http://www.fairbiotrade.org/).
3. and , Multifunctional bioenergy systems. The AGS Pathways Reports 2007: EU1. The Alliance for Global Sustainability, an international partnership between Chalmers University of Technology, Swiss Federal Institute of Technology Zurich, Massachusetts Institute of Technology and Tokyo University. Report available from AGS Office at Chalmers: GMV Chalmers, SE-412 96 Göteborg, Sweden. (2007).
4. Fate of heavy metals after application of sewage sludge and wood–ash mixtures to short-rotation willow coppice