All rights reserved, Freie Universität Berlin, 14195 Berlin, Germany.
The online documents and web pages including their parts are protected by copyright. They may only be copied and printed for private, scholarly and non-commercial use if they contain the copyright reference. The Freie Universität Berlin reserves the right to revoke this permission any time. Without prior written permission, no part of this publication may be reproduced, archived, translated, held on a server, posted in newsgroups, used in online services or put on a CD-ROM. It may be copied, though, on caches and proxy servers for the sole purpose of optimizing speed.
You are invited to quote the title and set links to our web site.