[26] Coe, John M. (2004), "The Integration of Direct Marketing and Field Sales to Form a New B2B Sales Coverage Model." Journal of Interactive Marketing, 18 (2), 62-74. [Liu]

Most of the investment in the 1990s in sales force automation or customer relationship management has not yielded better productivity. The integration of sales and marketing still remains a challenge to the business-to-business companies. And yet the buying process becomes more complicated due to the increased availability of information and global sourcing. Forward-looking companies have recognized these changes and are moving toward a new "sales coverage model." Companies integrate sales and marketing to achieve a more productive and accountable result. In principle, direct marketing should become part of sales. Across different stages of the customer life cycle, direct marketing and field sales are blended with varying levels of emphasis.