APA način citiranja

Brooke, H., & Helen Brooke. (1999). U.F.O.S. Oxford Bookworms Factfiles: Oxford University Press.

Čikaški stil citiranja

Brooke, Helen, i Helen Brooke. U.F.O.S. Oxford Bookworms Factfiles: Oxford University Press, 1999.

MLA način citiranja

Brooke, Helen, i Helen Brooke. U.F.O.S. Oxford Bookworms Factfiles: Oxford University Press, 1999.