Dimitrova, Miroslava. 2010. “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”. European Journal of Tourism Research 3 (2):135-37. https://doi.org/10.54055/ejtr.v3i2.57.