URL dokumen:
https://prisma.simaster.ugm.ac.id/karya_files/characteristics-of-nitrate-pollution-in-shallow-groundwater-on-the-south-slope-of-mount-merapi--yogyakarta--indonesia-dcfcd07e645d245babe887e5e2daa016/37dcd963-a9eb-11ee-abf0-e4434b0aade8