Miao, C. Fred, Donald J. Lund, and Kenneth Evans. Re-Examining the Influence of Career Stages on Salesperson Motivation: A Cognitive and Affective Perspective. Journal of Personal Selling & Sales Management 29 (лето 2009). С. 101–112; Robin T. Peterson. Beyond the Plateau. Sales & Marketing management (июль 1993). С. 78–82.