@book { EarlyBilingualismandMultilingualism,
    title = "Early Bilingualism and Multilingualism",
    author = "Zofia {Chłopek}",
    year = "2017",
    publisher = "Peter Lang Verlag",
    address = "Berlin, Germany",
    doi = "10.3726/978-3-653-06204-5",
    url = "https://www.peterlang.com/document/1049690"
}