Horn, K. (1967). Long-term Planning. The Institute of National Planning.
Citazione stile Chigago Style (17a edizione)Horn, Karl-Heinz. Long-term Planning. Cairo: The Institute of National Planning, 1967.
Citatione MLA (9a ed.)Horn, Karl-Heinz. Long-term Planning. The Institute of National Planning, 1967.
Attenzione: Queste citazioni potrebbero non essere precise al 100%.