Milt Grassell. What Purchasing Maangers Like in a Salesperson… and What Drives Them ip the Wall, Business Marketing (июнь 1986). С. 72–77. См. также Edith Cohen. The View from the Other Side, Sales & Marketing Management (June 1990). С. 108–110; and Ten Ways to Lose a Sale,Sales & Marketing Management (декабрь 1992). С. 35.