1. Appunn K., 2015. Coal in Germany [Online], Available from < https://www.cleanenergywire.org/factsheets/coal-germany> [13/02/2015].
2. ATEE – Club Biogaz, 2014.Tarifs 2011 et contratd’achatd’électricité issue de biogaz[Online], Availablefrom 23/10/2014.
3. EBA – European Biogas association. 2014. Biogas report 2014 [Online], Available from 12/2014.
4. RTE (Le réseau de l’Intelligence Electrique), 2015. Bilan électrique 2014 [Online], Availablefrom< http://www.rte-france.com/sites/default/files/bilan_electrique_2014.pdf>.
5. Stolpp S., 2014. Biogas market in Germany.German biogas association.http://www.biogas.org/edcom/webfvb.nsf/ID/DE_Homepage.