@book { EuropischesRechtundComputerreservierungssysteme,
    title = "Europäisches Recht und Computerreservierungssysteme",
    author = "Frank {Perret}",
    year = "2001",
    publisher = "Peter Lang Verlag",
    address = "Berlin, Germany",
    url = "https://www.peterlang.com/document/1090617"
}