Yuan, Guang, Dewen Kong, Lishan Sun, Wei Luo, and Yan Xu. “Connectivity Contribution to Urban Hub Network Based on Super Network Theory – Case Study of Beijing”. Promet - Traffic&Transportation 33, no. 1 (February 1, 2021): 35-47. Accessed June 20, 2021. https://traffic.fpz.hr/index.php/PROMTT/article/view/3536.