@article{GrueningNiemann1997,
  author    = {Gr{\"u}ning, H. and Niemann, K.},
  title     = {Bericht zum 14. Bochumer Workshop "Betrieb von Kl{\"a}ranlagen - Optimierung und Kosten sparen"},
  series = {Korrespondenz Abwasser},
  volume    = {44},
  journal   = {Korrespondenz Abwasser},
  number    = {Nr. 1},
  pages     = {29 -- 42},
  year      = {1997},
  language  = {de}
}
@article{GrueningOrthKnollmann1997,
  author    = {Gr{\"u}ning, H. and Orth, H. and Knollmann, J.},
  title     = {Untersuchungen zum Gaspotential von Faulschl{\"a}mmen},
  series = {Korrespondenz Abwasser},
  volume    = {44},
  journal   = {Korrespondenz Abwasser},
  number    = {Nr. 5},
  pages     = {884 -- 894},
  year      = {1997},
  language  = {de}
}