@book { GUIPrototyping,
    title = "GUI-Prototyping",
    author = "Marco {Bernal y Paños}",
    year = "2011",
    publisher = "GRIN Verlag",
    address = "München, Germany",
    doi = "10.3239/9783656037149",
    url = "https://www.hausarbeiten.de/document/180670"
}