[1] Univ Birmingham, Birmingham Business Sch, Edgbaston, Birmingham B15 2TT, England
[2] Johann Heinrich von Thunen Inst, Inst Rural Econ, Bundesallee 64, D-38116 Braunschweig, Germany
[3] Univ Adelaide, Fac Arts Business Law & Econ, Adelaide Business Sch, 12-10 Pulteney St, Adelaide, SA 5005, Australia