@book { FranzBrentanoCarlStumpfBriefwechsel18671917,
    title = "Franz Brentano-Carl Stumpf: Briefwechsel 1867–1917",
    author = "Margret {Kaiser-El-Safti}",
    year = "2015",
    publisher = "Peter Lang Verlag",
    address = "Berlin, Germany",
    doi = "10.3726/978-3-653-04550-5",
    url = "https://www.peterlang.com/document/1048614"
}