Tunkaew S, Thammatin T, Komonmit P. Uplifting Product Standards of Chiang Saen Learning Center, Chiang Rai Rajabhat University. RJPJ [Internet]. 2023 Jun. 30 [cited 2024 May 20];17(52):355-70. Available from: https://so05.tci-thaijo.org/index.php/RJPJ/article/view/260737