Lahallo, S.A. and Aritonang, R.D. 2020. Design of a Copy Service E-Marketplace Android-Based in the Parongpong District. Aptisi Transactions on Technopreneurship (ATT). 2, 1 (Feb. 2020), 59–67. DOI:https://doi.org/10.34306/att.v2i1.65.