1. Norin, E., "BIOGAS –Eller vad man kan gora av ruttna applen", Swedish Biogas Association, Stockholm, (1998).
2. Person, M., "Evaluation of upgrading techniques for biogas", Lund Institute of Technology, (2003).
3. Adl, M. and Omrani, G. A., "Background of biogas technology and its recent developments in Iran", International Journal of Global Energy Issues, Vol. 29, (2008), 3.
4. I.R. Iran Ministry of Agriculture, Agricultural Statistics Report, (2011).
5. Cristian, C. L. and Lahoti, A., "A biogas decision support system tool", Latin American and Caribbean Conference for Engineering and Technology “Innovation and Development for the Americas”, (2010).
6. Venetis, I.A., "Reinforcing investments in biogas technologies for small-scale RES applications in islands", Partner Responsible: University of Patras, (2009).
7. Polatidis, H., Haralambopoulos, D.A., Bruinsma, F., Vreeker, R. and Munda, G., "Decision Aid with the MCDA-RES software: A Wind-Hydro Energy Application for an Island of the Aegean, Greece", Energy Sources, Part B: Economics, Planning, Vol 4, (2009), 407–419.
8. Bojnec, S. and Papler, D., "Biogas energy development in slovenia", International Journal of Engineering, (2013), 77-86
9. Macharis, C., Springael, J., Brucker, K.D. and Verbeke, A., "PROMETHEE and AHP: The design of operational synergies in multi criteria analysis. Strengthening PROMETHEE with ideas of AHP", European Journal of Operational Research, (2004), 153: 307 – 317.
10. Behzadian, M., Kazemzadeh, R.B., Albadvi, A. and Aghdasi, M., "PROMETHEE: A comprehensive literature review on methodologies and applications", European Journal of Operational Research, Vol 22, (2010), 198-215.
11. Szczypinska, A. and Piotrowski, E.W., "Projective market model approach to AHP decision making", Physical a-Statistical Mechanics and Its Applications, Vol 15, (2008), 3982–3986.
12. Yang, J. and Lee, H., "An AHP decision model for facility location selection", Facilities, Vol 15, (1997), 241–254.
13. Tzeng, G.H., Teng, M.H., Chen, J.J. and Opricovic S., "Multi criteria selection for a restaurant location in Taipei", International Journal of Hospitality Management, Vol 21, (2002), 171–187.
14. Saaty, T.L., "The analytic hierarchy process: planning, priority setting, resource allocation", New York/London: McGraw-Hill International Book Co, (1980).
15. Rahman, S. and Frair, L.C., "A hierarchical approach to electric utility planning", International Journal of Energy Research, Vol 8, (1984),185–196.
16. Zong, W. and Zhihong, W., "Mitigation assessment results and priorities for China’s energy sector", Applied Energy, Vol 56, (1997), 237–251.
17. Akash, B.A., Mamlook, R. and Mohsen, M.S., "Multi-criteria selection of electric power plants using analytical hierarchy process" Electric Power Systems Research, Vol 52, (1999), 29–35.
18. Ou, X., Zhang, X., Chang, S. and Guo, Q., "Energy consumption and GHG emissions of six biofuel pathways by LCA in (the) People’s Republic of China", Applied Energy, Vol 86, (2009), 5197–5208.
19. Energy Technology Perspectives. International Energy Agency, (2010).
20. Afazeli, H., Jafari, A., Rafiee, SH. and Nosrati, M., "An investigation of biogas production potential from livestock and slaughterhouse wastes", Renewable and Sustainable Energy Reviews, Vol 34, (2014), 380–386.
21. Plöch, M. and Heiermann, M., "Biogas farming in central and northern Europe: a strategy for developing countries? Agricultural Engineering International: the CIGRE journal, Vol 8, (2006), 1–15.
22. Rajendran, K., Aslanzadeh, S. and Taherzadeh, M.J., "House holding as digesters-a review", Energies, Vol 5, (2012), 2911–2942.
23. Cheng, S., Zifu, L., Mang, H.P., Huba, E.M., Gao, R. and Wang, X., "Development and application of prefabricated biogas digesters in developing countrie", Renewable and Sustainable Energy Reviews, Vol 34, (2014), 387–400.