Sobczak, Paweł. 2014. “Changes in the Schedule at the Koleje Śląskie Sp. Z o.o. And Their Impact on the Operations of the Carrier and Sustainable Transport in the Silesia Province”. Forum Scientiae Oeconomia 2 (4):77-90. https://ojs.wsb.edu.pl/index.php/fso/article/view/291.