Legal provisions for mandatory referendums at national level

Direct Democracyin Asia: A ReferenceGuide to the Legislation and Practice (2005), page 89 on Cambodia: There is no mechanism in for direct democracyin Cambodia. However, there had been practices of referendum:  in 1945 (independence), 1955 (approving  policies), 1958  (reducing number of representatives),  1959 (suspending  provincial parliaments), 1960 (approving sihanouk and policies), 1961 (shorteningschool vacations), 1972 (constitutional referendum). There have been no directdemocracy practices found ever since.

Source: http://www.docstoc.com/docs/74258274/Direct-Democracy-in-Asia