APA (7th ed.) Citation

Hamilton, R., Perry, J. H., & Michael, I. (1984). The Poem of the Cid. Penguin.

Chicago Style (17th ed.) Citation

Hamilton, Rita, Janet H. Perry, and Ian Michael. The Poem of the Cid. London [etc.]: Penguin, 1984.

MLA (9th ed.) Citation

Hamilton, Rita, et al. The Poem of the Cid. Penguin, 1984.