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one person signed up on pumpipumpe.ch and offers tools, a bike and a lot of other stuff - seems like a good person to connect to. - Update: we talked with the person living at Brunnengasse 2. He did not know anything about pumpipumpe and was not very enthusiastic about sharing. For more questions ask Arno Döpper
(another person signed up in Merseburg)
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https://www.couchsurfing.com/people/naser.sadeghi - Bad Dürrenberg, Architect - Update: Bodhi Neiser said he was contacted but didn't reply. Not sure though.
https://www.couchsurfing.com/people/okrimnnamhel - BdD - interest in 'old buildings' 
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