Kumar, V. (2013). Profitable Customer Engagement: Concepts, Metrics, and Strategies. SAGE Publications India Pvt. Ltd.
Lua i Stíl Chicago (17ú heag.)Kumar, V. Profitable Customer Engagement: Concepts, Metrics, and Strategies. New Delhi: SAGE Publications India Pvt. Ltd, 2013.
Lua MLA (9ú heag.)Kumar, V. Profitable Customer Engagement: Concepts, Metrics, and Strategies. SAGE Publications India Pvt. Ltd, 2013.
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