APA-viite (7. p.)

Willis, R. E. (1987). A guide to forecasting for planners and managers. Prentice-Hall.

Chicago-viite (17. p.)

Willis, Raymond E. A Guide to Forecasting for Planners and Managers. Englewood Cliffs, N.J: Prentice-Hall, 1987.

MLA-viite (9. p.)

Willis, Raymond E. A Guide to Forecasting for Planners and Managers. Prentice-Hall, 1987.