Engert, M. (1969). Problems of Long-term Planning in the German Democratic Republic. The Institute of National Planning.
Style de citation Chicago (17e éd.)Engert, Manfred. Problems of Long-term Planning in the German Democratic Republic. Cairo: The Institute of National Planning, 1969.
Style de citation MLA (9e éd.)Engert, Manfred. Problems of Long-term Planning in the German Democratic Republic. The Institute of National Planning, 1969.