Farkas, B. “PRESENTATION OF THE RAIL FREIGHT MARKET’S CONCENTRATION WITH RESPECT TO THE GAS MARKET WITH THE HELP OF THE HERFINDAL-HIRSCHMAN INDEX”. Science and Transport Progress , no. 6(66) (December 25, 2016): 69–78. Accessed April 6, 2025. https://stp.ust.edu.ua/article/view/90474.