@book { Laproductivitlpreuvedesservices,
    title = "La productivité à l’épreuve des services",
    author = "Faridah {Djellal} and Faïz {Gallouj}",
    year = "2012",
    publisher = "Peter Lang Verlag",
    address = "Bruxelles, Belgium",
    doi = "10.3726/978-3-0352-6170-7",
    url = "https://www.peterlang.com/document/1044138"
}