Dimitrova, M. Opportunities for Improving Congress tourismʼs Competitiveness: Supervisor: Prof. Tichomir Pelov, Ph.D, University of National and World Economy, Sofia, Bulgaria Institution Awarding the Ph. D. Degree: University of National and World Economy, Sofia, Bulgaria Date of Defence: 25 Th March 2010. EJTR 2010, 3, 135-137.