Universität Jena; ESchmu(at)aol.com
Accepted 21 July 2003 by F. W. Hehl
Loughborough, UK; c.a.hoenselaers(at)lboro.ac.uk
Received 29 March 2003, revised 13 May 2003,
accepted 28 May 2003 by F. W. Hehl
(1) Institute for Physics of Microstructures RAS, 603600 Nyzhny Novgorod, GSP-105, Russia; (2) Westfälische Wilhelms-Universität, Wilhelm-Klemm-Str. 10, 48149 Münster; jersch(at)uni-muenster.de
Received 14 January 2003, revised 2 June 2003,
accepted 17 June 2003 by U. Eckern
Universität Augsburg, Institut für Physik, Theoretische Physik II, 86135 Augsburg, Germany; lueckt(at)physik.uni-augsburg.de
Received 14 April 2003, revised 30 June 2003,
accepted 3 July 2003 by U. Eckern
Oxford University; peter.holland(at)green.ox.ac.uk
Received 23 June 2003, accepted 21 July 2003 by F. W. Hehl
Institute of Physics, University of Augsburg, 86135 Augsburg, Germany;
markus.schmid(at)physik.uni-augsburg.de, arno.kampf(at)physik.uni-augsburg.de
Received 29 July 2003, accepted 5 August 2003 by U. Eckern
(1)Institute of Physics, University of Augsburg, 86135 Augsburg, Germany; (2)NEST-INFM and Dipartimento di Fisica, Universita die Roma Tre, 00146 Roma, Italy; peter.schwab(at)physik.uni-augsburg.de
Received 6 August 2003, accepted 14 August 2003 by U. Eckern