Are referendum results binding?

Sri Lanka
- Mandatory referendum - always
- Optional referendum - always
Constitutionof the Democratic Socialist Republic of Sri Lanka
(Adoptedin 1978, last amended in 2001)
http://www.priu.gov.lk/Cons/1978Constitution/Chapter_11_Amd.html
Article79. (Mandatory referendum)
The Speaker shall endorse on every Bill passed byParliament a certificate in the following form :-
“This Bill (here state the short title of the Bill)has been duly passed by Parliament.”
Such certificate may also state the majority by whichsuch Bill was passed :
Provided that where by virtue of the provisions ofArticle or Article 83 or Article 84 or Article 123 (2) a special majority isrequired for the passing of a Bill, the Speaker shall certify such Bill only ifsuch Bill has been passed with such special majority:
Provided further that where by virtue of Article 83,the Bill or any provision thereof requires the approval of the People at aReferendum, such certificate shall further state that the Bill or suchprovision shall not become law until approved by the People at a Referendum.
Article 80. (Optional referendum)
(1) Subject to the provisions of paragraph (2) of thisArticle, a Bill passed by Parliament shall become law when the certificate ofthe Speaker is endorsed thereon.
(2) Where the Cabinet of Ministers has certified thatany Bill or any provision thereof is intended to be submitted for approval bythe People at a Referendum or where the Supreme Court has determined that a Billor any provision thereof requires the approval of the People at a Referendum orwhere any Bill is submitted to the People by Referendum under paragraph (2) ofArticle 85, such Bill or such provision shall become law upon being approved bythe People at a Referendum in accordance with paragraph (3) of Article 85 onlywhen the President certifies that the Bill or provision thereof has been soapproved. The President shall endorse on every Bill so approved a certificatein the follow?ing form : -