APA (7th ed.) Citation

Dunn, L., Hardy, A. C., & Hardy, M. J. (1941). A book of ships. Penguin Books.

Chicago Style (17th ed.) Citation

Dunn, Laurence, A. C. Hardy, and M. J. Hardy. A Book of Ships. Harmondsworth, Middlesex ; New York: Penguin Books, 1941.

MLA (9th ed.) Citation

Dunn, Laurence, et al. A Book of Ships. Penguin Books, 1941.