@book { BilingualerUnterricht,
    title = "Bilingualer Unterricht",
    author = "Gerhard {Bach} and Susanne {Niemeier}",
    year = "2000",
    publisher = "Peter Lang Verlag",
    address = "Berlin, Germany",
    doi = "10.3726/978-3-653-01111-1",
    url = "https://www.peterlang.com/document/1067392"
}