@book { ControllingimEBusiness,
    title = "Controlling im E-Business",
    author = "Wolfgang {Berens} and Walter {Schmitting}",
    year = "2018",
    publisher = "Peter Lang Verlag",
    address = "Berlin, Germany",
    doi = "10.3726/b13849",
    url = "https://www.peterlang.com/document/1068411"
}