1. Department of Economics, Helmut Schmidt University, Holstenhofweg 85, P.O.B. 700822, 22008 Hamburg, Germany
2. Department of Economics, University of Pretoria, Pretoria 0002, South Africa
3. Research Institute for Energy Management and Planning, University of Tehran, No. 13 Qods St, Tehran, Iran
4. Centre for Fashion Business and Innovation Research, Fashion Business School, London College of Fashion, University of the Arts London, 272 High Holborn, London, WC1V 7EY, United Kingdom