@misc{WetterElmar2008,
  author    = {Wetter, Christof and Elmar, Br{\"u}gging},
  title     = {Decentralized Production of Bioethanol - State of Art and Perspectives 4. European Bioethanol Technology Meeting},
  address   = {Detmold},
  year      = {2008},
  language  = {en}
}
@misc{WetterElmar2008,
  author    = {Wetter, Christof and Elmar, Br{\"u}gging},
  title     = {Guidelines for Construction of Biogas Plants. Recommended Procedures and Instructions; 16th European Biomass Conference \& Exhibition From Research to Industry and Markets},
  address   = {Valencia},
  year      = {2008},
  language  = {en}
}