Horn, K. H. (1967). Productivity , Concepts and Measurement. The Institute of National Planning.
Chicago-viite (17. p.)Horn, Karl Heinz. Productivity , Concepts and Measurement. Cairo: The Institute of National Planning, 1967.
MLA-viite (9. p.)Horn, Karl Heinz. Productivity , Concepts and Measurement. The Institute of National Planning, 1967.
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