1. Kendra M., Babin M., Šulko P., BulTrans-2013 – Anniversary scientific conference on aeroanutics, automative and railway engineering and technologies, 95–97 (Sofia, Bulgaria, 2013)
2. Comparison of Chosen Environmental Aspects in Individual Road Transport and Railway Passenger Transport
3. Gros I., Barančík I., Čujan Z., Velká kniha logisitky (Prague, Czech Republic, 2016)
4. Šulgan M., Gnap J., Majerčák J., Postavenie dopravy v logistike (University of Zilina, Slovak Republic, 2008)
5. Proposal of Backbone Public Transport Lines in the Upper Šariš Region