https://books.google.co.id/books?id=aeAg1X7afOoC&pg=PA877&lpg=PA877&dq=planet88&source=bl&ots=0w-xWiojy2&sig=ACfU3U0XnbidQXTNJ9KZ1eEf8r9wCyHwqw&hl=id&sa=X&ved=2ahUKEwjDztv8sciFAxXsSmwGHaEmDf8
https://books.google.co.id/books?id=aeAg1X7afOoC&pg=PA877&lpg=PA877&dq=planet88&source=bl&ots=0w-xWiojy2&sig=ACfU3U0XnbidQXTNJ9KZ1eEf8r9wCyHwqw&hl=id&sa=X&ved=2ahUKEwjDztv8sciFAxXsSmwGHaEmDf8