Legal provisions for mandatory 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
Part 7, I, Amendment of theConstitution, Participation in Elections and Referenda, Article 175
(Amended on 17 May 1987)
If a law is adopted by a three-fifthsor less than two-thirds majority of the total number of votes of the Assemblyand is not referred by the President for further consideration, it shall bepublished in the Official Gazette and shall be submitted to referendum.