Παραπομπή σε μορφή APA (7η εκδ.)

Zappulla, J. (2016). Critical selling: How top performers accelerate the sales process and close more deals. John Wiley & Sons, Inc.. https://doi.org/10.1002/9781119172512

Παραπομπή σε μορφή Chicago (17η εκδ.)

Zappulla, Justin. Critical Selling: How Top Performers Accelerate the Sales Process and Close More Deals. Hoboken, New Jersey: John Wiley & Sons, Inc., 2016. https://doi.org/10.1002/9781119172512.

Παραπομπή σε μορφή MLA (8th εκδ.)

Zappulla, Justin. Critical Selling: How Top Performers Accelerate the Sales Process and Close More Deals. John Wiley & Sons, Inc., 2016. https://doi.org/10.1002/9781119172512.