@book { DerKreuzfahrtmarktEineMarktanalyse,
    title = "Der Kreuzfahrtmarkt. Eine Marktanalyse",
    author = "Anja {Fischer}",
    year = "2007",
    publisher = "GRIN Verlag",
    address = "München, Germany",
    doi = "10.3239/9783638605861",
    url = "https://www.hausarbeiten.de/document/67966"
}