Montaño-Valle, A. “Sustainability Strategy As a Source of Competitive Advantages in the Tourism Industry. A Model for the Integration of Natural Resources: Supervisors: Dr. Alfonso Vargas-Sánchez. Institution Awarding the Ph. D. Degree: University of Huelva, Spain. Date of Defence: 30/06/2015”. European Journal of Tourism Research, vol. 14, Oct. 2016, pp. 106-9, https://ejtr.vumk.eu/index.php/about/article/view/247.