Engert, M. (1969). Problems of Long-term Planning in the German Democratic Republic. The Institute of National Planning.
Chicago-referens (17:e uppl.)Engert, Manfred. Problems of Long-term Planning in the German Democratic Republic. Cairo: The Institute of National Planning, 1969.
MLA-referens (9:e uppl.)Engert, Manfred. Problems of Long-term Planning in the German Democratic Republic. The Institute of National Planning, 1969.
Varning: dessa hänvisningar är inte alltid fullständigt riktiga.