“ECONOMIC VALUATION USING TRAVEL COST METHOD (TCM) IN KILIM KARST GEOFOREST PARK, LANGKAWI, MALAYSIA”. JOURNAL OF TROPICAL FOREST SCIENCE 31, no. 1 (January 30, 2019): 078–089. Accessed October 12, 2025. https://jtfs.frim.gov.my/jtfs/article/view/175.