“PREDICTING PERFORMANCE OF FRONTLINER: ASSESSING THE ROLES OF MOTIVATION, WORK DISCIPLINE, ENVIRONMENT PT KERETA API PARIWISATA DAOP VI YOGYAKARTA”. Jurnal Optimal 23, no. 1 (July 8, 2026): 1–16. Accessed October 3, 2026. https://jurnal.stieieu.ac.id/index.php/opt/article/view/191.