@book { EscriturasdelYoenlaobradeMigueldeUnamuno,
    title = "Escrituras del Yo en la obra de Miguel de Unamuno",
    author = "Berit {Callsen}",
    year = "2019",
    publisher = "Peter Lang Verlag",
    address = "Berlin, Germany",
    doi = "10.3726/b15557",
    url = "https://www.peterlang.com/document/1110883"
}