Faculty of Management, Czestochowa University of Technology,
Armii Krajowej 19 B, 42-200 Częstochowa, Poland
Submission date: 2016-01-07
Final revision date: 2016-01-17
Acceptance date: 2016-01-22
Publication date: 2016-05-25
Pol. J. Environ. Stud. 2016;25(3):1263–1270