[1] Univ Foggia, Dept Econ, Largo Papa Giovanni Paolo 2,1, I-71121 Foggia, Italy
[2] Univ Milan, Dept Agr & Environm Sci Prod Landscape & Agroener, Via Giovanni Celoria 2, I-20133 Milan, Italy
[3] Univ Johannesburg, Fac Engn & Built Environm, Dept Qual & Operat Management, APB Campus,POB 524,Auckland Pk, ZA-2006 Johannesburg, South Africa