@book { Dienstleistungsmarketing,
    title = "Dienstleistungsmarketing",
    author = "Eva {Thelen} and Gaby B. {Mairamhof}",
    year = "2021",
    publisher = "Peter Lang Verlag",
    address = "Berlin, Germany",
    url = "https://www.peterlang.com/document/1113947"
}