อิ่มประเสริฐ ก. Factors of Direct Marketing Influenced Purchasing Behavior of the Consumers in Bangkruai District Nonthaburi Province. rpujournal [internet]. 2018 May 27 [cited 2026 Jan. 8];4(1):122-34. available from: https://so03.tci-thaijo.org/index.php/rpu/article/view/125765