@book { Reisefotografie,
    title = "Reisefotografie",
    subtitle = "Städte, Berge, Meer, Gebäude, Landschaften. Mit wertvollen Praxis-Tipps",
    author = "Bernhard {Kämmer}",
    year = "2010",
    publisher = "humboldt",
    address = "Hannover, Deutschland",
    url = "https://schluetersche.openpublishing.com/document/403500"
}