Legal provisions for optional referendums at national level

Lithuania
CONSTITUTION OF THE REPUBLIC OF LITHUANIA
(Adopted1992; last amended 2006)
http://www3.lrs.lt/home/Konstitucija/Constitution.htm
Article 9
The most significant issues concerning the life of theState and the Nation shall be decided by referendum. In the cases established by law, the Seimas shallannounce a referendum. A referendumshall also be announced if not less than 300,000 citizens with the electoralright so request. The procedure for theannouncement and execution of a referendum shall be established by law.
REFERENDUMLAW
(Adopted 2002; lastamended 2012)
http://www3.lrs.lt/pls/inter3/dokpaieska.showdoc_e?p_id=437744
Article 5. Consultative (Deliberative)Referendums
Consultative (deliberative) referendums may be held withrespect to other issues of utmost importance to the State and the People,regarding which it is not necessary to hold a mandatory referendum, they arebeing proposed for a referendum by 300 thousand citizens having the right tovote or the Seimas.
Article 9. Rightof Initiative of Calling Referendum
1. The right ofinitiative of calling a referendum shall belong to the citizens and the Seimas.
2. The citizens’ rightof calling a referendum shall be conducted through the petition of 300 thousandcitizens who are eligible.
3. A group comprisingat least one-fourth of the Seimas Members may submit to the Seimas a proposalto call a referendum. A decision on this proposal shall be adopted inaccordance with the procedure set forth by the Seimas Statute.