ชุมวงศ์ ก. “The Working Operation Motivation of Policemen for the Crime Suppression Division about Natural Resources and the Environmen”. Journal of Rattana Bundit University, vol. 13, no. 2, Dec. 2018, pp. 49-60, https://so03.tci-thaijo.org/index.php/rbac/article/view/224646.