@book { HeilungunwirksamerBauvertragsklauseln,
    title = "Heilung unwirksamer Bauvertragsklauseln",
    author = "Johannes {Kuffer}",
    year = "2021",
    publisher = "Peter Lang Verlag",
    address = "Berlin, Germany",
    url = "https://www.peterlang.com/document/1107149"
}