Gabriel, H. W. (1962). Twenty steps to power, influence and control over people / H.W. Gabriel. Prentice-Hall.
Chicago-viite (17. p.)Gabriel, H. W. Twenty Steps to Power, Influence and Control over People / H.W. Gabriel. Englewood Cliffs, N.J: Prentice-Hall, 1962.
MLA-viite (9. p.)Gabriel, H. W. Twenty Steps to Power, Influence and Control over People / H.W. Gabriel. Prentice-Hall, 1962.
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