@book { Etrebilingue,
    title = "Etre bilingue",
    author = "Georges {Lüdi} and Bernard {Py}",
    year = "1986",
    publisher = "Peter Lang Verlag",
    address = "Lausanne, Switzerland",
    doi = "10.3726/978-3-0351-0647-3",
    url = "https://www.peterlang.com/document/1043655"
}