<human>: Background: Muhammad Yunus (Bengali: muhaammd iunuus; born 28 June 1940) is a Bangladeshi social entrepreneur, banker, economist, and civil society leader who was awarded the Nobel Peace Prize for founding the Grameen Bank and pioneering the concepts of microcredit and microfinance. These loans are given to entrepreneurs too poor to qualify for traditional bank loans. In 2006, Yunus and the Grameen Bank were jointly awarded the Nobel Peace Prize "for their efforts through microcredit to create economic and social development from below". The Norwegian Nobel Committee said that "lasting peace cannot be achieved unless large population groups find ways in which to break out of poverty" and that "across cultures and civilizations, Yunus and Grameen Bank have shown that even the poorest of the poor can work to bring about their own development".
Context: After his graduation, Yunus joined the Bureau of Economics as a research assistant to the economics researches of Professor Nurul Islam and Rehman Sobhan. Later, he was appointed lecturer in economics in Chittagong College in 1961. During that time, he also set up a profitable packaging factory on the side. In 1965, he received a Fulbright scholarship to study in the United States. He obtained his PhD in economics from the Vanderbilt University Graduate Program in Economic Development (GPED) in 1971. From 1969 to 1972, Yunus was assistant professor of economics at Middle Tennessee State University in Murfreesboro.  During the Bangladesh Liberation War in 1971, Yunus founded a citizen's committee and ran the Bangladesh Information Center, with other Bangladeshis in the United States, to raise support for liberation. He also published the Bangladesh Newsletter from his home in Nashville. After the War, he returned to Bangladesh and was appointed to the government's Planning Commission headed by Nurul Islam. However, he found the job boring and resigned to join Chittagong University as head of the Economics department. After observing the famine of 1974, he became involved in poverty reduction and established a rural economic program as a research project. In 1975, he developed a Nabajug (New Era) Tebhaga Khamar (three share farm) which the government adopted as the Packaged Input Programme. In order to make the project more effective, Yunus and his associates proposed the Gram Sarkar (the village government) programme. Introduced by president Ziaur Rahman in the late 1970s, the Government formed 40,392 village governments as a fourth layer of government in 2003. On 2 August 2005, in response to a petition by Bangladesh Legal Aids and Services Trust (BLAST) the High Court had declared village governments illegal and unconstitutional.  His concept of microcredit for supporting innovators in multiple developing countries also inspired programs such as the Info lady Social Entrepreneurship Programme. CANNOTANSWER
Question: What did Yunus joined after graduation?. Whats the answer?
<bot>: the Bureau of Economics as a research assistant