Copyright
Pictures may only be used for editorial and non-commercial purposes. This material may be used for editorial, general educational and scientific purposes, without prior permission and free of charge, where there is no infringement of copyright and the source is clearly stated (Copyright: BENTELER International AG, source: benteler.com). All other forms of use, in particular commercial as well as any falsification of, or alterations to, the pictures (e.g. digital or mechanical) are expressly forbidden.