Legal provisions for optional referendums at national level

Turkey
TheConstitution of the Republic of Turkey
(Adopted in7 November 1982, last amended 17 October 2001)
http://www.anayasa.gov.tr/images/loaded/pdf_dosyalari/THE_CONSTITUTION_OF_THE_REPUBLIC_OF_TURKEY.pdf
(Optional referendum)
Section D - Duties and Powers
Article 104.
The President of the Republic is theHead of the state. In this capacity he or she shall represent the Republic ofTurkey and the unity of the Turkish Nation; he or she shall ensure the implementationof the Constitution, and the regular and harmonious functioning of the organsof state.
To this end, the duties he or sheshall perform, and the powers he or she shall exercise, in accordance with theconditions stipulated in the relevant articles of the Constitution are asfollows:
Thoserelating to legislation:
[…] to submit to referendum, if he orshe deems it necessary, legislation regarding amendment of the Constitution.[…]
Part 7, I, Amendment of theConstitution, Participation in Elections and Referenda,
Article 175.(Amendedon 17 May 1987)
[…]The President of the Republic mayrefer the laws related to the Constitutional amendments for furtherconsideration. If the Assembly adopts the draft law referred by the Presidentby a two-thirds majority, the President may submit the law to referendum. […]
[…]A law on the Constitutionalamendment adopted by a two- thirds majority of the total number of members ofthe Turkish Grand National Assembly directly or if referred back by thePresident for further consideration, or its articles as considered necessary maybe submitted to a referendum by the President. […]
[…]The Turkish Grand NationalAssembly, in adopting the laws related to the Constitutional amendment, shallalso decide on which provisions shall be submitted to referendum together andwhich shall be submitted individually. […]