@book { Gibraltarim18Jahrhundert,
    title = "Gibraltar im 18. Jahrhundert",
    author = "Jochen {Hausmann}",
    year = "2015",
    publisher = "Peter Lang Verlag",
    address = "Berlin, Germany",
    doi = "10.3726/978-3-653-05188-9",
    url = "https://www.peterlang.com/document/1049095"
}