[1] YALE UNIV, DEPT STAT, NEW HAVEN, CT 06520 USA
[2] BROWN UNIV, DIV APPL MATH, PROVIDENCE, RI 02912 USA
[3] UNIV CALIF BERKELEY, DEPT STAT, BERKELEY, CA 94720 USA
[4] CARNEGIE MELLON UNIV, DEPT PSYCHOL, PITTSBURGH, PA 15213 USA
[5] UNIV OXFORD, OXFORD OX1 3TG, ENGLAND
[6] ISAAC NEWTON INST MATH SCI, CAMBRIDGE, ENGLAND
[7] UNIV GLASGOW, DEPT STAT, GLASGOW G12 8QQ, SCOTLAND
[8] UNIV TORONTO, DEPT PREVENT MED & BIOSTAT, TORONTO M5S 1A8, ONTARIO, CANADA
[9] UNIV KENT, INST MATH & STAT, CANTERBURY CT2 7NF, KENT, ENGLAND