[1] UNIV AMSTERDAM,NETHERLANDS CTR GEOECOL RES,LANDSCAPE & ENVIRONM RES GRP,NL-1018 VZ AMSTERDAM,NETHERLANDS
[2] IOWA STATE UNIV,DEPT STAT,AMES,IA 50011
[3] OREGON STATE UNIV,DEPT STAT,CORVALLIS,OR 97331
[4] AFRC,ROTHAMSTED EXPT STN,HARPENDEN AL5 2JQ,HERTS,ENGLAND
[5] UNIV SYDNEY,DEPT AGR CHEM & SOIL SCI,SYDNEY,NSW 2006,AUSTRALIA