Legal provisions for optional referendums at national level

Mozambique
Constitution of theRepublic of Mozambique
(adopted in 2004)
(English translation)
http://confinder.richmond.edu/admin/docs/Constitution_(in_force_21_01_05)(English)-Mozlegal.pdf
Article 136 (1) and (2).
1. Citizens who have beenregistered as voters within the national territory, and those living abroad whohave been properly registered as voters, may be called to take part inreferenda on major national issues.
2. The decision to call areferendum shall be taken by the President of the Republic upon therecommendation of the Assembly of the Republic, approved by an absolutemajority of its members and on the initiative of at least one third of thedeputies.