[1] UNIV CAMERINO,CTR INTERDIPARTIMENTALE CALCOLO,I-62032 CAMERINO,ITALY
[2] VRIJE UNIV BRUSSELS,INST PHARMACEUT,B-1090 BRUSSELS,BELGIUM
[3] ORGANON INT BV,ANALYT RES & DEV LABS,5340 BH OSS,NETHERLANDS
[4] PHILIPS RES LABS,NAT LAB WB 512,5600 MD EINDHOVEN,NETHERLANDS