@book { SchwierigesprachlicheStrukturen,
    title = "Schwierige sprachliche Strukturen",
    author = "Bernhard {Engelen}",
    year = "2011",
    publisher = "Peter Lang Verlag",
    address = "Berlin, Germany",
    doi = "10.3726/978-3-653-00931-6",
    url = "https://www.peterlang.com/document/1054122"
}