@book { DieSegmentsystemedesDeutschenunddesBulgarischen,
    title = "Die Segmentsysteme des Deutschen und des Bulgarischen",
    author = "Ruska K. {Simeonova}",
    year = "1989",
    publisher = "Biblion",
    address = ", Germany",
    doi = "10.3726/b12213",
    url = "https://www.peterlang.com/document/1066751"
}