Krajangchom, S. ., . K. Sangkakorn, and N. Poonsukcharoen. “The Adaptation Strategy of Tourism in Upper North of Thailand under the COVID-19 Pandemic”. University of the Thai Chamber of Commerce Journal Humanities and Social Sciences, vol. 41, no. 1, Mar. 2021, pp. 1-20, https://so06.tci-thaijo.org/index.php/utccjournalhs/article/view/243464.