Defence date: 7 June 1996Examining board: Prof. Michel Dobry, Paris X-Nanterre (co-supervisor) ; Prof. Gérard Duprat, Paris XIII-Vincennes ; Prof. Massimo La Torre, IUE ; Prof. Alessandro Pizzorno IUE (supervisor) ; Prof. Arpad Szakolczai, IUEFirst made available online on 24 September 2013