Cita APA (7a ed.)

Gordon, P. D., & Gray, S. J. (1994). United kingdom. Routledge.

Cita Chicago Style (17a ed.)

Gordon, Paul D., y Sidney J. Gray. United Kingdom. London [etc.]: Routledge, 1994.

Cita MLA (9a ed.)

Gordon, Paul D., y Sidney J. Gray. United Kingdom. Routledge, 1994.