Authors
Zbigniew Spyra
University of Economics in Katowice Faculty of Informatics and Communication, Department of Market and Marketing Research,, Katowice, Poland
Olgierd Witczak
olgierd.witczak@ue.katowice.pl
University of Economics in Katowice Faculty of Informatics and Communication, Department of Business and Consumer Relationship Management,, Katowice, Poland