Any links to external Web sites or returned from supplied Web search engines are provided as a courtesy. They should not be construed as an endorsement of the content or views of the linked materials by the operator of this Web site.

A link shall give the visitor – in the context of the paragraph where the link arises – a better understanding of the object that is underlaid with this link. For example, if the operator mentions the city Aachen, the underlaying link determines which "Aachen" is exactly meant.