Karner, Thomas, Sylvia Scharl, and Brigitte Weninger. “Estimation of the Domestic Transport Performance from the Consolidated European Road Freight Transport Data”. Austrian Journal of Statistics 43, no. 1 (April 15, 2014): 49–62. Accessed May 11, 2021. https://ajs.or.at/index.php/ajs/article/view/43_1_3.