Pastor, Ludwig Freiherr von..
The History of the Popes from the Close of the Middle Ages.- Second Edition. Vol.  XX.. Gregory VIII. (1572-1585). /
Edited by Ralph Francis Kerr 
. - St. Louis : B. Herder, Book Co.,  1930 
. - xxiii, 670  p.  22 cm. 
 - ((Pastor's History of the Popes). )