¹Department of Organizations and Political Systems, University of Bologna, Bologna, Italy

Correspondence: Giovan Francesco Lanzara, Department of Organizations and Political Systems, University of Bologna, Via dei Bersaglieri 6, I - 40125 Bologna, Italy. E-mail: lanzara@spbo.unibo.it

Received 18 September 2005; Revised 23 September 2005; Accepted 28 September 2005.