@book { Elespaolysuestructura,
    title = "El español y su estructura",
    subtitle = "Segunda edición",
    author = "Silvia {Burunat} and Ángel L. {Estévez} and Aleksín H. {Ortega}",
    year = "2012",
    publisher = "Peter Lang Verlag",
    address = "New York, United States of America",
    url = "https://www.peterlang.com/document/1109300"
}