@book { MultichannelManagement,
    title = "Multichannel Management",
    author = "Gottfried {Gruber}",
    year = "2018",
    publisher = "Peter Lang Verlag",
    address = "Berlin, Germany",
    doi = "10.3726/b13906",
    url = "https://www.peterlang.com/document/1068457"
}