linsel, h., & sack, k. (1965). theoretical problems of investment planning. National Planning Institute.
Παραπομπή σε μορφή Chicago (17η εκδ.)linsel, hermann, και kurt sack. Theoretical Problems of Investment Planning. cairo: National Planning Institute, 1965.
Παραπομπή σε μορφή MLA (9th εκδ.)linsel, hermann, και kurt sack. Theoretical Problems of Investment Planning. National Planning Institute, 1965.