Zelenika, Ratko, and Drago Pupavac. “Intellectual Capital- Developmental Resource of Logistic Companies for 21’ Century”. Promet - Traffic&Transportation 15, no. 1 (January 25, 2003): 37–41. Accessed August 26, 2025. https://traffic2.fpz.hr/index.php/PROMTT/article/view/2015.