@book { CommunityBasedTourism,
    title = "Community Based Tourism",
    author = "Manuela {Margraf}",
    year = "2005",
    publisher = "Diplom.de",
    address = "Hamburg, Germany",
    doi = "10.3239/9783832489632",
    url = "https://m.diplom.de/document/224124"
}