[1] Univ Waterloo, Dept Stat & Actuarial Sci, Waterloo, ON N2L 3G1, Canada
[2] Univ Rennes 1, CREM, F-35000 Rennes, France
[3] Univ Rennes 1, IGR IAE Rennes, F-35000 Rennes, France
[4] Univ Freiburg, Dept Math Stochast, D-79104 Freiburg, Germany
[5] Vrije Univ Brussel, Dept Econ, B-1050 Brussels, Belgium