Wiefel, M., and M. Gregus. “Digitalization: The New Digital Consumer and the Change of Companies Value Chain”. International Journal of Sciences: Basic and Applied Research (IJSBAR), vol. 21, no. 1, Apr. 2015, pp. 378-8, https://gssrr.org/index.php/JournalOfBasicAndApplied/article/view/3635.