นิลสาคู วิษณุ, and วงศฺธนวสุ ศุภวัฒนากร. 2017. “Knowledge Understanding and practice related to traffic sign of high school students in Khon Kaen municipality, khon Kaen Province”. Local Administration Journal 10 (4):139-63. https://so04.tci-thaijo.org/index.php/colakkujournals/article/view/116899.