- Arts & Humanities Through the Eras. Detroit, MI: Thomson/Gale, 2005. Print. Reference NX 440 .A787 2005
- Bonhomme, Brian, and Cathleen Boivin, eds. Milestone Documents in World History: Exploring the Primary Sources that Shaped the World. Dallas, TX: Schlager Group, 2010. Print. Reference D5 .M5594 2010
- CAIN Web Service - Conflict and Politics in Northern Ireland
- New York Times Historical Database (1851-2009)