Sepadyati, N. “An Exploration of Risks Involved in Managing Supplier Portfolio in Multinational Companies Operating in Indonesia”. Jurnal Teknik Industri: Jurnal Keilmuan Dan Aplikasi Teknik Industri, vol. 21, no. 2, Dec. 2019, pp. 79-90, doi:10.9744/jti.21.2.79-90.