1. University of Sussex Business School, University of Sussex, Brighton BN1 9SN, United Kingdom;
2. Saïd Business School, University of Oxford, Oxford OX1 1HP, United Kingdom;
3. Department of Computer Science, University of Mons, 7000 Mons, Belgium;
4. School of Mathematical Sciences and IMA-Shanghai, Shanghai Jiao Tong University, Shanghai 200240, China