The Web site is designed with the markup language XHTML 1.0 Strict. Formerly I was accustomed to create HTML code that opens links referring external Web sites in a new browser window without the influence of the user. But the Strict variant of XHTML 1.0 does not allow such an approach. The user shall always decide on her resp. his own to open a link in the same or in a new browser window. For example, state-of-the-art browsers support the

< Ctrl - Key > + < Left Mouse Button >

shortcut for opening a link in a new browser instance. Therefore I would like to give the visitor a help to recognize external links on this Web site. If the mouse pointer hovers over a text link the appearance will change but the kind of the change depends on whether the link refers an external or an internal Web site:
Test it by moving the mouse over the links below:

Internal Link

External Link