1. Derivatives Research and Validation Group, Rabobank, Graadt van Roggenweg 400, 3531 AH, Utrecht, The Netherlands
2. CWI — National Research Institute for Mathematics and Computer Science, Science Park 123, 1098 XG, Amsterdam, The Netherlands
3. Delft Institute of Applied Mathematics, Delft University of Technology, Mekelweg 4, 2628 CD, Delft, The Netherlands