Energy! ahead : energy report of the City of Vienna / owner and publisher: Vienna City Administration Municipal Department 20 - Energy Planning. Vienna : Vienna City Administration Municipal Department 20 - Energy Planning, December 2014- : (2018). Wienbibliothek im Rathaus, https://resolver.obvsg.at/urn:nbn:at:AT-WBR-428975 / Urheberrechtsschutz (InC 1.0)