Tietze, Wolf, and Marie-Luise Steinmann-Tietze. “Technical and Structural Innovations to European Transport in 21’1 Century”. Promet - Traffic&Transportation 11, no. 2-3 (October 11, 2012): 41–55. Accessed August 27, 2025. https://traffic2.fpz.hr/index.php/PROMTT/article/view/2316.