@book { ProduktinnovationundPerformance,
    title = "Produktinnovation und Performance",
    subtitle = "Eine empirische Analyse des deutschen Ernährungsgewerbes",
    author = "Antje {Wittkopp}",
    year = "2004",
    publisher = "Peter Lang Verlag",
    address = "Berlin, Germany",
    url = "https://www.peterlang.com/document/1097932"
}