Dinfa, P. 2023. STUDY OF THE DEVELOPMENT OF WASTEWATER TREATMENT SYSTEMS AND THE YUAN ISLAND AS A TOURIST ATTRACTION OF NAKHON SAWAN MUNICIPALITY’S YUAN CHUAN RAK CANAL FOR DEVELOPING A GEOGRAPHICAL DATABASE AND PROGRAMED INSTRUCTION. Journal of MCU Nakhondhat. 10, 9 (Sep. 2023), 158–170.