ANKARA, April 16 (Reuters) - Turkish President Tayyip Erdogan called the prime minister and the leader of nationalist party to congratulate them on the result of Sunday's referendum, which were "clear", presidential sources said on Sunday. Sources in Erdogan's office said he told Prime Minister Binali Yildirim he was grateful to the nation for showing its will at the polls. With 98.2 percent of the ballot boxes opened, 51.31 percent of the votes were for "Yes", backing the referendum, the state-run Anadolu agency reported.
