Siswanto, S., Dewi Yustiana, Koen Irianto Uripan, S. Sutomo, and Siti Nur Soleha. “The Effect of Competency Certification on Employee Performance With Competency Testing As a Variable Mediation (Study at PT. X)”. Jurnal Ekonomi, vol. 15, no. 01, Jan. 2026, pp. 14-29, https://ejournal.seaninstitute.or.id/index.php/Ekonomi/article/view/8086.