[Plombin, Ch., & Hugosson, B. (2003). TrendSetter report No 2003:3, Biogas as Vehicle Fuel: A European Overview. Stockholm.]Search in Google Scholar
[Persson, M., Jönsson, O, & Wellinger, A. (2006). Biogas upgrading to vehicle fuel standards and grid injection, Task 37: Energy from biogas and landfill gas. IEA Bioenergy.]Search in Google Scholar
[Biogas as a road transport fuel: an assessment of the potential role of biogas as a renewable transport fuel. (2006). National Society for Clean Air and Environmental Protection.]Search in Google Scholar
[Blumberga, D., Dzene, I., Al Sedi, T., Rucs, D., Prasls, H., Ketners, M., Finstervalders, T., Folka, S., & Jansens, R. (2008). Biogāzes rokasgrāmata. Rīga: Ekodoma.]Search in Google Scholar
