@book { RiskClassificationbyMeansofClustering,
    title = "Risk Classification by Means of Clustering",
    author = "Bernhard Christian {Kübler}",
    year = "2010",
    publisher = "Peter Lang Verlag",
    address = "Berlin, Germany",
    doi = "10.3726/978-3-653-00279-9",
    url = "https://www.peterlang.com/document/1054273"
}