1. Annual trade of energy;Ministry of Economy Trade and Industry,2010
2. Annual report on the environment, the sound material-cycle society and the biodiversity in Japan 2009;Ministry of the Environment,2009
3. Annual report on trends in forest and forestry, fiscal year 2008;Forestry Agency,2009
4. Current situation and problems for using wood biomass;Kuboyama,2008
5. Economic analysis on small-scale forest biomass gacification considering regional resource distribution and technical characteristics;Yagi;J Jpn Inst Energy,2007