@book { DerKristallalsexpressionistischesSymbol,
    title = "Der Kristall als expressionistisches Symbol",
    author = "Henrik {Leschonski}",
    year = "2021",
    publisher = "Peter Lang Verlag",
    address = "Berlin, Germany",
    url = "https://www.peterlang.com/document/1105008"
}