URL dokumen:
https://prisma.simaster.ugm.ac.id/karya_files/comparison-of-vs30-value-from-microtremor-data-based-on-spt-drill-test-of-young-merapi-deposits-in-opak-river--yogyakarta-dcfcd07e645d245babe887e5e2daa016/dad1b389-d196-11ef-8115-00505691351c