[1] UNIV AMSTERDAM, STERRENKUDIG INST ANTON PANNEKOEK, 1018 WB AMSTERDAM, NETHERLANDS
[2] KONINKLIJKE STERRENWACHT, B-1180 BRUSSELS, BELGIUM
[3] OBSERV ROYAL BELGIQUE, B-1180 BRUSSELS, BELGIUM
[4] UNIV FED RIO JANEIRO, BR-20080 RIO DE JANEIRO, BRAZIL
[5] INST ASTROFIS ANDALUCIA, E-18080 GRANADA, SPAIN
[6] APPALACHIAN STATE UNIV, DEPT PHYS & ASTRON, BOONE, NC 28608 USA
[7] EUROPEAN SO OBSERV, SANTIAGO 19, CHILE
[8] INST ASTRON, S-22100 LUND, SWEDEN
[9] UNIV LIEGE, INST ASTROPHYS, B-4200 COINTE OUGREE, BELGIUM
[10] LEIDEN OBSERV, 2300 RA LEIDEN, NETHERLANDS
[11] COPENHAGEN UNIV OBSERV, DK-4340 TOLLOSE, DENMARK
[12] OBSERV GENEVA, CH-1290 SAUVERNY, SWITZERLAND
[13] UNIV ANTWERP, RIJKSUNIV CTR ANTWERP, ASTROPHYS RES GRP, B-2020 ANTWERP, BELGIUM
[14] UNIV FED MINAS GERAIS, DEPT FIS ICEX, BR-30161 BELO HORIZONTE, MG, BRAZIL