Vengel, A. A. (2010). 20 minutes to a top performer: Three fast and effective conversations to motivate, develop, and engage your employees. Mcgraw-Hill.
Παραπομπή σε μορφή Chicago (17η εκδ.)Vengel, Alan A. 20 Minutes to a Top Performer: Three Fast and Effective Conversations to Motivate, Develop, and Engage Your Employees. New York , N.Y: Mcgraw-Hill, 2010.
Παραπομπή σε μορφή MLA (9th εκδ.)Vengel, Alan A. 20 Minutes to a Top Performer: Three Fast and Effective Conversations to Motivate, Develop, and Engage Your Employees. Mcgraw-Hill, 2010.
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