Civelek, Mehmet, Krzysztof Gajdka, Jaroslav Světlík, and Vladimír Vavrečka. “Differences in the Usage of Online Marketing and Social Media Tools: Evidence from Czech, Slovakian and Hungarian SMEs”. Equilibrium. Quarterly Journal of Economics and Economic Policy 15, no. 3 (September 7, 2020): 537–563. Accessed March 22, 2023. http://economic-research.pl/Journals/index.php/eq/article/view/1810.