@book { CitizenRelationshipManagement,
    title = "Citizen Relationship Management",
    author = "Alexander {Schellong}",
    year = "2011",
    publisher = "Peter Lang Verlag",
    address = "Berlin, Germany",
    doi = "10.3726/978-3-653-01059-6",
    url = "https://www.peterlang.com/document/1054022"
}