Bulgarian Academy of Science;
Union of Scientists in Bulgaria;
Faculty for Organization and
Informatics, Varazdin,
Croatia;
Faculty of Economy and Business Administration,
University of Craiova, Romania;
Department of Economics and Administrative Sciences,
Fatih University, Istanbul, Turkey;
Faculty
of Economics and Management, University
of Defense,
Czech Republic;
Department of Forestry and
Natural Environment,
Department
of Business Administration,
School of Business and Economics,