@book { BiografischeStudiezurPersonundzumWerkFriedrichFrbels,
    title = "Biografische Studie zur Person und zum Werk Friedrich Fröbels",
    author = "Detlef {Krone}",
    year = "2015",
    publisher = "Peter Lang Verlag",
    address = "Berlin, Germany",
    doi = "10.3726/978-3-653-03943-6",
    url = "https://www.peterlang.com/document/1048214"
}