@book { AlternativeTourismonGranCanaria,
    title = "Alternative Tourism on Gran Canaria",
    subtitle = "The diversification of tourism products as an alternative to mass tourism",
    author = "Franziska {Herms}",
    year = "2006",
    publisher = "Diplom.de",
    address = "Hamburg, Deutschland",
    doi = "10.3239/9783832492816",
    url = "https://m.diplom.de/document/224403"
}