Fachbereich Physik, Philipps-Universität Marburg, 35032 Marburg, Germany;
florian.gebhard(at)physik.uni-marburg.de
Received 13 Sep 2004, accepted 26 Nov by U. Eckern
University of Missouri, Department of Physics and Astronomy, Columbia, MO 65211, USA; MashhoonB(at)missouri.edu
Received 2 Nov 2004, accepted 26 Nov 2004 by F. W. Hehl
II. Institut für Theoretische Physik, Universität Hamburg, Luruper Chaussee 149,
22761 Hamburg, Germany;
bernd.kuckert(at)desy.de
Received 30 Nov 2004, accepted 1 Dec 2004 by K. Fredenhagen
Department of Physics, Faculty of Science, Ege University, 35100 Bornova-Izmir,
Turkey;
mgerceklioglu(at)hotmail.com
Received 22 Jul 2004, revised 30 Sep 2004, accepted 17 Dec
2004 by U. Eckern
Max-Planck-Institut für Sonnensystemforschung, 37191 Katlenburg-Lindau,
Germany;
marsch(at)linmpi.mpg.de
Received 6 Oct 2004, accepted 10 Jan 2005 by U. Eckern