@book { FacilityManagement,
    title = "Facility Management",
    subtitle = "Handbuch für Studium und Praxis",
    author = "Hanspeter {Gondring} and Thomas {Wagner}",
    year = "2018",
    publisher = "Vahlen",
    address = "München, Deutschland",
    url = "https://vahlen.openpublishing.com/document/1219094"
}