[1] European History. (n.d.). Retrieved June 10, 2017, from http://www.historyhome.co.uk/europe/causeww1.htm#b
[2] Firstworldwar.com. (n.d.). Retrieved June 10, 2017, from http://www.firstworldwar.com/origins/causes.htm
[3] Jünger, E., & Hofmann, M. (2016). Storm of steel. New York: Penguin Books.
[4] Barthas, L., & Strauss, E. M. (2015). Poilu: the World War I notebooks of Corporal Louis Barthas, barrelmaker, 1914-1918. New Haven: Yale University Press.
[5] May, C. C., Harrison, G., & Crane, D. (2015). To fight alongside friends: the First World War diary of Charlie May. London: William Collins.
[6] Hart, P. (2013). The Great War, 1914-1918. London: Profile.
[7] T. (n.d.). The Great War. Retrieved March 18, 2017, from https://www.youtube.com/user/TheGreatWar
United States in World War I. (2017, June 30). Retrieved June 11, 2017, from https://en.wikipedia.org/wiki/United_States_in_World_War_I#War_declared
The United States before World War I. (2015, December 14). Retrieved June 11, 2017, from http://alphahistory.com/worldwar1/united-states/
Russia before World War I. (2015, December 15). Retrieved June 11, 2017, from http://alphahistory.com/worldwar1/russia/
P. (2007, September 04). Imperial Russia. Retrieved June 11, 2017, from http://portalus.ru/modules/english_russia/rus_readme.php?subaction=showfull&id=1188905942&archive=&start_from=&ucat=&
Austria-Hungary before World War I. (2015, December 15). Retrieved June 11, 2017, from http://alphahistory.com/worldwar1/austria-hungary/
First Battle of the Aisne. (2017, July 11). Retrieved July 11, 2017, from https://en.wikipedia.org/wiki/First_Battle_of_the_Aisne
First Battle of the Marne. (2017, June 10). Retrieved June 11, 2017, from https://en.wikipedia.org/wiki/First_Battle_of_the_Marne
Battle of Mons. (2017, June 10). Retrieved June 11, 2017, from https://en.wikipedia.org/wiki/Battle_of_Mons