Tian, Chao, Juan Peng, Wen Zhang, Shuai Zhang, and Jian Wang. “Tourism Environmental Impact Assessment Based on Improved AHP and Picture Fuzzy PROMETHEE II Methods”. Technological and Economic Development of Economy 26, no. 2 (February 3, 2020): 355-378. Accessed April 24, 2024. https://journals.vilniustech.lt/index.php/TEDE/article/view/11413.