Yang, Byunghwa, Youngchan Kim, Richard G. McFarland. Individual Differences and Sales Performance: A Distal-Proximal Mediation of Model of Self Efficacy, Conscientiousness, and Extraversion. Journal of Personal Selling & Sales Management 31 (осень 2011), стр. 371–382.; Thomas Rollins. How to Tell Competent Salespeople from the Other Kind. Sales & Marketing Management (сентябрь 1990), стр. 116–118, 145–146; см. также Timothy J. Trow. The Secret of a Good Hire: Profiling. Sales & Marketing Management (май 1990), С. 44–55.