@book { VolunteerTourism,
    title = "Volunteer Tourism",
    author = "Katja {Schluzy}",
    year = "2011",
    publisher = "Diplom.de",
    address = "Hamburg, Deutschland",
    doi = "10.3239/9783842810778",
    url = "https://m.diplom.de/document/228355"
}