Singapore's President S. R. Nathan and Senior Minister Goh Chok Tong Friday extended their birthday greetings to former president of South Africa Nelson Mandela for his 90th birthday.
In his congratulation letter, Nathan said Mandela has made immeasurable contributions to South Africa and remains a role model for others in the Africa continent and other developing nations.
He said Mandela's "unremitting support of worthy causes continues to bring benefits to many people today". 
Former South African President Nelson Mandela waves during the 46664 concert held in his honour in Hyde Park, London June 27, 2008. Nathan also recalled his trip to Robben Island, the place where the freedom fighter was incarcerated.
Goh, also Singapore's former prime minister, wrote in his congratulation letter about his fond memories of several meetings between them, especially during Mandela's state visit to Singapore in 1997.
Goh expressed his wish to call on Mandela when he visits South Africa next year.
Source:Xinhua