pubs/tests/bibexamples/utf8.bib

@book{hausdorff1949grundzüge,
    author = {Hausdorff, Felix},
    title = {Grundzüge der Mengenlehre},
    publisher = {Chelsea Pub. Co},
    year = {1949},
    address = {New York},
    isbn = {978-0-8284-0061-9}
}