GEORGINA LUKANOVA, G. L. 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, [S. l.], v. 6, n. 1, p. 88–91, 2013. Disponível em: https://ejtr.vumk.eu/index.php/about/article/view/123. Acesso em: 19 oct. 2021.