linsel, h., & sack, k. (1965). theoretical problems of investment planning. National Planning Institute.
Chicago-referens (17:e uppl.)linsel, hermann, och kurt sack. Theoretical Problems of Investment Planning. cairo: National Planning Institute, 1965.
MLA-referens (9:e uppl.)linsel, hermann, och kurt sack. Theoretical Problems of Investment Planning. National Planning Institute, 1965.