1. Axelrod, R. (1984) The Evolution of Cooperation, New York: Basic Books.
2. Butterfield, H. (1950) Christianity and History, New York: Scribner.
3. Butterfield, H. (1952) History and Human Relations, New York: Palgrave Macmillan.
4. Collins, S. (2008) The Hunger Games, New York: Scholastic.
5. Collins, S. (2009) Catching Fire, New York: Scholastic.