@misc{Wetter1993,
  author    = {Wetter, Christof},
  title     = {Environmental compatibility test for waste water treatment plants, 1. Chinese and German Environmental Protection Technique Interchange Conference, Chongqing/China, Dezember 1993},
  year      = {1993},
  language  = {en}
}
@misc{Wetter1993,
  author    = {Wetter, Christof},
  title     = {Requirements for state-of-the-art-treatment of industrial waste in the Federal Repulic of Germany 1. Chinese and German Environmental Protection Technique Interchange Conference, Chongqing/China, Dezember 1993},
  year      = {1993},
  language  = {en}
}