Requirements for a referendum to pass
Singapore
Constitution of the Republic of Singapore
(adopted in 9 August 1965, last amended 2010)
http://www.wipo.int/wipolex/en/text.jsp?file_id=188429#LinkTarget_8238
Part II
Amendment of Constitution
(2) A Bill seeking to amend any provision in this Constitutionshall not be passed by Parliament unless it has been supported on Second andThird Readings by the votes of not less than two-thirds of the total number ofthe elected Members of Parliament referred to in Article 39 (1) (a).
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[…] shall not be passed by Parliament unless it has also beensupported at a national referendum by not less than two-thirds of the totalnumber of votes cast by the electors registered under the ParliamentaryElections Act (Cap. 218).
Part III