@misc{guerrero18,
    author = "D. Guerrero and A. Millan and J. Juan and J. Viejo and M.~J. Bellido and P. Ruiz-de-Clavijo  and E. Ostua",
    title = {Dispositivo Electrónico Calculador de Funciones Trigonométricas y Usos del Mismo},
    year = 2018,
    month = "November",
    day = {22},
    note = {P201831133},
    url = {}
}

@misc{guerrero16,
    author = "D. Guerrero and M.~J. Bellido and J. Juan and A. Millan and P. Ruiz-de-Clavijo and J. Viejo and E. Ostua",
    title = {Circuito Electrónico Digital para el Cálculo de Senos y Cosenos de Múltiplos de un Ángulo},
    year = 2016,
    month = "October",
    day = {10},
    note = {P201600865},
    url = {https://www.dte.us.es/id2/lib/exe/fetch.php?media=es:patent:traslado_iet.pdf}
}