Denny Saputera, MohdHaizam Saudi, and Obsatar Sinaga. “PETROCHEMICAL INDUSTRY RAW MATERIAL SPREAD UPSTREAM TO DOWNSTREAM IN THE PANDEMIC COVID-19 PERIOD”. PalArch’s Journal of Archaeology of Egypt / Egyptology, vol. 17, no. 10, Jan. 2021, pp. 1352-71, https://archives.palarch.nl/index.php/jae/article/view/4833.