Gregg, J. V., Hossell, C. H., & Richardson, J. T. (1964). Mathematical trend curves: An aid to forecasting. Edinburgh: Oliver and Boyd.
Παραπομπή Chicago StyleGregg, J. V., C. H. Hossell, and J. T. Richardson. Mathematical Trend Curves: An Aid to Forecasting. Edinburgh: Oliver and Boyd, 1964.
Παραπομπή MLAGregg, J. V., C. H. Hossell, and J. T. Richardson. Mathematical Trend Curves: An Aid to Forecasting. Edinburgh: Oliver and Boyd, 1964.
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