Miguel José Oliveira and  Fátima Farinha and  Elisa M. J. da Silva and  Rui Lança and  Manuel Duarte Pinheiro and  Cátia Miguel,  Observatory of Sustainability of the Algarve Region for Tourism: Proposal for Environmental and Sociocultural Indicators.   journal   = {International Journal of Humanities and Social Sciences}, [online]. World Academy of Science, Engineering and Technology.
    August 2019, vol. 153(9). 1237 - 1244
    [viewed 14 November 2019]. Available from: https://publications.waset.org/pdf/10010749.