Ministry of Foreign Affairs. Foreign Minister's address at Eminent Persons Lecture at S. Rajaratnam School of International Studies (RSIS) 22 November 2010. 2012-03-03. (原始内容存档于2011-08-09).
Ministry of Foreign Affairs. Foreign Minister's address at Eminent Persons Lecture at S. Rajaratnam School of International Studies (RSIS) 22 November 2010. 2012-03-03. (原始内容存档于2011-08-09).