1. Anderson, A., Watson, T., Shannon, C. 2011. Electricity in Indonesia–Investment and taxation guide 2011. PricewaterhouseCoppers. Retrieved from www.pwc.com/id.
2. APROBI, 2011. Status kapasitas aktual industry biodiesel Indonesia 2011. (W. W. Purwanto, Interviewer).
3. 1,3-Propanediol production by fermentation: an interesting way to valorize glycerin from the ester and ethanol industries;Barbarito;Ind. Crops Prod.,1998
4. Palm oil plantation through sustainable plantations;Basiron;Lipid Sci. Technol.,2007
5. Bickel, P., Friedrick, R. 2005. Externalities of energy methodology 2005 update. Stutgart: European Comission Community Research. Retrieved from http://www.externe.info.