BOLEK, Vladimír. The Effects of Information Systems and Information Technologies as a Key Factor in Increasing the Competitiveness of Companies. In Logos Polytechnikos. - Jihlava : Vysoká škola polytechnická, 2021. ISSN 2464-7551, 2021, roč. 12, č. 3, s. 98-115 online. VEGA 1/0388/20.