Georgina Lukanova, G. L. (2013). Improving Service Effectiveness in the High-Class Hotels in Varna (Bulgaria): Supervisor: Assoc. Prof. Tanya Dabeva, PhD Institution awarding the Ph. D. Degree: University of Economics-Varna, Bulgaria th Date of defence: 19 October 2012. European Journal of Tourism Research, 6(1), 88–91. Retrieved from https://ejtr.vumk.eu/index.php/about/article/view/123