Fabio Padovano; Roberto Ricciuti, eds. (2007). "Appendix 2". Italian Institutional Reforms: A Public Choice Perspective. Springer Science & Business Media. p. 35. ISBN978-0-387-72141-5.
Daniela Giannetti; Michael F. Thies (2011). "Electoral Reform and ractional Politics in Italy and Japan". In Daniela Giannetti; Bernard Grofman (eds.). A Natural Experiment on Electoral Law Reform: Evaluating the Long Run Consequences of 1990s Electoral Reform in Italy and Japan. Springer Science & Business Media. p. 79. ISBN978-1-4419-7228-6.