Novotná, Michaela, and Dalibor Gottwald. “Current Challenges for the Postal Services Sector in the Context of E-Commerce – Predictive Analysis of V4 States”. Promet - Traffic&Transportation 33, no. 6 (December 13, 2021): 919–930. Accessed August 26, 2025. https://traffic2.fpz.hr/index.php/PROMTT/article/view/2976.