@book { FormelhafteIrRegularitten,
    title = "Formelhafte (Ir-)Regularitäten",
    author = "Sören {Stumpf}",
    year = "2015",
    publisher = "Peter Lang Verlag",
    address = "Berlin, Germany",
    doi = "10.3726/978-3-653-06078-2",
    url = "https://www.peterlang.com/document/1067627"
}