His Die Geschichtstheologie des heiligen Bonaventura, 1959.
His Faith, philosophy, and theology, c1985 t.p. (Joseph Cardinal Ratzinger) introd. (Cardinal Ratzinger)
Wikipedia, viewed Apr. 19, 2005 (Pope Benedict XVI; b. Joseph Alois Ratzinger, Apr. 16, 1927, Marktl am Inn, Bavaria; elected Pope of the Roman Catholic Church, Apr. 19, 2005); Feb. 28, 2013 (b. Joseph Aloisius Ratzinger)
Vatican: the Holy See, viewed Apr. 20, 2005 (habemus Papam ... Josephum ... Cardinalem Ratzinger, qui sibi nomen imposuit Benedictum XVI; Benedikt XVI; Benedict XVI; Benedicto XVI; Benoît XVI; Benedetto XVI; Bento XVI)
NEWS.VA, viewed Feb. 28, 2013 Vatican Information Service article dated Feb. 26 (Benedict XVI will be "Pontiff emeritus" or "Pope emeritus"; he will keep the name of "His Holiness, Benedict XVI"; the last day of his Pontificate will be 28 Feb.; the Sede Vacante will begin at 8:00pm) Vatican Radio article dated Feb. 28 (the Pontificate of Pope Benedict XVI will come to an end with the Sede Vacante beginning at 8pm Rome time)