@book { WilliamSternoderStrebennachEinheit,
    title = "William Stern oder Streben nach Einheit",
    author = "Gerald {Bühring}",
    year = "2021",
    publisher = "Peter Lang Verlag",
    address = "Berlin, Germany",
    url = "https://www.peterlang.com/document/1083808"
}