K. Ohkawa - University of Bremen
M. Behringer - University of Bremen
H. Wenisch - University of Bremen
M. Fehrer - University of Bremen
B. Jobst - University of Bremen
D. Hommel - University of Bremen
M. Kuttler - Institute of Solid State Physics, TU-Berlin, Hardenbergstr. 36, D-10623 Berlin, Germany
M. Strassburg - Georgi Nadjakov Institute of Solid State Physics
D. Bimberg - Georgi Nadjakov Institute of Solid State Physics
G. Bacher - University of Würzburg
D. Tönnies - University of Würzburg
A. Forchel - University of Würzburg