@book { DerGMPVertragausbauvergaberechtlicherSicht,
    title = "Der GMP-Vertrag aus bauvergaberechtlicher Sicht",
    author = "Mathias {Mantler}",
    year = "2021",
    publisher = "Peter Lang Verlag",
    address = "Berlin, Germany",
    url = "https://www.peterlang.com/document/1096247"
}