9Markku Suksi, Bringing in the People: A Comparison of Constitutional Forms and Practices of the Referendum[ M ]. Boston: Martinus Nijhoft, 1993 : 137 - 142.
10David Butler, Austin Ranney. Referendums around the world: The Growing Use of Direct Democracy[ M]. Washington, D. C. : American Enterprise Institute Press, 1994 : 5.