Davis, E. J. (1988). Practical sales forecasting. Mc Graw - Hill.
Chicago Style aipamenaDavis, E. J. Practical Sales Forecasting. London: Mc Graw - Hill, 1988.
MLA aipamenaDavis, E. J. Practical Sales Forecasting. Mc Graw - Hill, 1988.
Kontuz: berrikusi erreferentzia hauek erabili aurretik.