Issues in relation to which referendums are optional at the national level

Iran, Islamic Republic of
Constitutionof the Islamic Republic of Iran
(Adoptedin 3 December 1979, 28 July 1989)
http://www.alaviandassociates.com/documents/constitution.pdf
(Optional referendum)
CHAPTER V Article 59.
In extremely importanteconomic, political, social, and cultural matters, the function of the legislaturemay be exercised through direct recourse to popular vote through a referendum.Any request for such direct recourse to public opinion must be approved bytwo-thirds of the members of the Islamic Consultative Assembly.