Castelluccio, Francesco, Mario Catalano, Davide Fichera, Marco Migliore, and Salvatore Amoroso. “Standardization of Road Danger Signs in the European Union”. Promet - Traffic&Transportation 27, no. 1 (March 1, 2015): 1-11. Accessed April 20, 2024. http://traffic.fpz.hr/index.php/PROMTT/article/view/1504.