Pasmawati, Y., A. E. Tontowi, B. Hartono, and T. Wijayanto. “Determination of Favourite Market for 3D-Printer Product Based Online Platform”. International Review of Management and Marketing, vol. 8, no. 5, Aug. 2018, pp. 18-23, https://econjournals.com/index.php/irmm/article/view/6906.