@book { Mehrgterflsse,
    title = "Mehrgüterflüsse",
    subtitle = "Multicommodity Flows",
    author = "Bastian {Rückel}",
    year = "2014",
    publisher = "Diplom.de",
    address = "Hamburg, Deutschland",
    url = "https://m.diplom.de/document/282385"
}