@book { SustainableTransportationinEuropeWhatPublicTransportHastoOfferintheFuture,
    title = "Sustainable Transportation in Europe. What Public Transport Has to Offer in the Future",
    author = "Elias {Beetz}",
    year = "2015",
    publisher = "GRIN Verlag",
    address = "München, Germany",
    url = "https://www.hausarbeiten.de/document/306535"
}