@book { TopicMaps,
    title = "Topic Maps",
    subtitle = "An Enabling Technology for Knowledge Management and its Implementation",
    author = "Knud {Steiner}",
    year = "2002",
    publisher = "Diplom.de",
    address = "Hamburg, Deutschland",
    doi = "10.3239/9783832450229",
    url = "https://m.diplom.de/document/220172"
}