[1] DEUTSCH BUNDESPOST FTZ,FORSCHUNGSINST,D-6100 DARMSTADT,FED REP GER
[2] RHEIN WESTFAL TH AACHEN,SFB 202,BASISLABOR,D-5100 AACHEN,FED REP GER
[3] TECH UNIV BERLIN,INST FESTKORPERPHYS 1,D-1000 BERLIN,FED REP GER
[4] THOMSON CSF,CENT RECH LAB,F-91401 ORSAY,FRANCE