Legal provisions for optional referendums at national level

Viet Nam
1992 Constitution of the Socialist Republic ofVietnam
(adopted in 9 November 1946 , amended in 25December 2001)
http://www.na.gov.vn/htx/English/C1479/?cateid=1479#isSI4SFeT3Hz
Article84(14).
TheNational Assembly has the following duties and powers:
The referendum of October 1955 was held duringthe period the country was divided, and thus only in the then South Vietnam. In north Vietnam, there has never been any referendums. Directdemocracy is currently a live debate in some Vietnamese circles!