Prologomena to St. Ambrose - From the Nicene and Post-Nicene Fathers of the Christian Church, second series, vol. 10. Introduction to the life and writings of St. Ambrose, with a timeline. - http://www.ccel.org/ccel/schaff/npnf210.toc.html
The Ecole Initiative: Ambrose of Milan - Article on the career of St. Ambrose, by Ivor J. Davidson. Includes an extensive bibliography. - http://www2.evansville.edu/ecoleweb/articles/ambrose.html
Ambrose, Saint - Biographical entry in the Columbia Encyclopedia. Includes short bibliography. - http://www.bartleby.com/65/am/Ambrose.html
Ambrose of Milan, Bishop and Doctor - Brief biography, with some asides on Arianism, and prayer in traditional and contemporary language. - http://elvis.rowan.edu/~kilroy/JEK/12/07.html
Catholic Encyclopedia: St. Ambrose - Article on the life and teachings of this Bishop of Milan, and Doctor of the Church, who died in 397. - http://www.newadvent.org/cathen/01383c.htm
Lives of Saints: Ambrose of Milan - Profile of this bishop, confessor, and Doctor of the Church. From the book "Lives of Saints," published by John J. Crawley. - http://www.catholic-forum.com/saints/sta07001.htm