Sources

https://sites.google.com/site/thehistoryofforeignpolicy2013/u-s-allies-and-enemies-wwi

https://sites.google.com/site/thehistoryofforeignpolicy2013/u-s-allies-and-enemies-wwi/key-events

http://www.timetoast.com/timelines/world-war-1--75

http://www.nzhistory.net.nz/files/images/bulgaria.jpg

https://www.mtholyoke.edu/~raina20s/ww1/play.html