Veruska C. Dutra and  Afonso R. Aquino,  Monitoring of Key Indicators of Sustainable Tourism in the Jalapão State Park/Tocantins: A Case Study of Environmental Indicators.   journal   = {International Journal of Social and Business Sciences}, [online]. World Academy of Science, Engineering and Technology.
    October 2016, vol. 119(11). 3641 - 3646
    [viewed 16 April 2024]. Available from: https://publications.waset.org/pdf/10005781.