Bamford, C., Brunskill, K., Gordon, C., Grant, S., Munday, S., & Walton, S. (2002). AS level and A level: Economics. New York: Cambridge University Press.

Bamford, Colin, Keith Brunskill, Cain Gordon, Sue Grant, Stephen Munday, and Stephen Walton. AS Level and A Level: Economics. New York: Cambridge University Press, 2002.

Bamford, Colin, et al. AS Level and A Level: Economics. New York: Cambridge University Press, 2002.