https://books.google.co.id/books?id=IiJCAQAAMAAJ&pg=PA318&lpg=PA318&dq=planet88&source=bl&ots=L7zMWKhBgP&sig=ACfU3U3IrfaPRvorSWMWErrQCscxuWiMBg&hl=id&sa=X&ved=2ahUKEwi-zaSXirOFAxUaTGwGHXFfBz0
https://books.google.co.id/books?id=IiJCAQAAMAAJ&pg=PA318&lpg=PA318&dq=planet88&source=bl&ots=L7zMWKhBgP&sig=ACfU3U3IrfaPRvorSWMWErrQCscxuWiMBg&hl=id&sa=X&ved=2ahUKEwi-zaSXirOFAxUaTGwGHXFfBz0