1. EurObserv'ER. Biogas barometer;SYSTÈMES SOLAIRES le journal des énergies renouvelables,2010
2. Biogas upgrading to vehicle fuel standards and grid injection;Persson,2006
3. Biogas upgrading technologies – developments and innovations;Petersson,2009
4. Techniques for transformation of biogas to biomethane;Ryckebosch;Biomass Bioenergy,2011
5. Lombardi L, Baciocchi R, Carnevale E, Corti A, Costa G, Gabarrell X, et al. Innovative processes for biogas upgrading. In: Proceedings of Sardinia 2011, thirteenth international waste management and landfill symposium; 3–7 October 2011; Margherita di Pula S, Cagliari, Italy: CISA Publisher.