APA (7th ed.) Citation

Balfour, S., & Preston, P. (1999). Spain and the great powers in the twentieth century. Routledge.

Chicago Style (17th ed.) Citation

Balfour, Sebastian, and Paul Preston. Spain and the Great Powers in the Twentieth Century. London [etc.]: Routledge, 1999.

MLA (9th ed.) Citation

Balfour, Sebastian, and Paul Preston. Spain and the Great Powers in the Twentieth Century. Routledge, 1999.