@book { BlockfltenunterrichtindererstenHlftedes20Jahrhunderts,
    title = "Blockflötenunterricht in der ersten Hälfte des 20. Jahrhunderts",
    author = "Gabriele {Puffer}",
    year = "2021",
    publisher = "Peter Lang Verlag",
    address = "Berlin, Germany",
    url = "https://www.peterlang.com/document/1091487"
}