Greenberg, David. "9/11 Attack." Dictionary of American History. Ed. Stanley I. Kutler. 3rd ed. Vol. 6. New York: Charles Scribner's Sons, 2003. 108-109. Gale Virtual Reference Library. Web. 10 May 2011.
"Dresden, Bombing Of." Encyclopedia of U.S. National Security. Ed. Richard J. Samuels. Vol. 1. Thousand Oaks, CA: Sage Reference, 2006. 218-219. Gale Virtual Reference Library. Web. 10 May 2011.
Boyer, Paul S. "Hiroshima." Encyclopedia of Genocide and Crimes Against Humanity. Ed. Dinah L. Shelton. Vol. 1. Detroit: Macmillan Reference USA, 2005. 442-444. Gale Virtual Reference Library. Web. 12 May 2011.