Contact:
Helge Lüddemann Medical Physics Section Carl von Ossietzky-Universität Oldenburg D-26111 Oldenburg Germany e-mail: h.lueddemann_AT_uni-oldenburg.de phone: +49 441 798 5472 fax: +49 441 798 3902 office location: W2 0-084 Note: substitute _AT_ by @ within the email addresses, please