APA

Pickering R., . (2006). Complete biology for Cambridge igcse. New York: Oxford University Press.

Chicago

Pickering Ron, . 2006. Complete biology for Cambridge igcse. New York: Oxford University Press.

Harvard

Pickering R., . (2006). Complete biology for Cambridge igcse. New York: Oxford University Press.

MLA

Pickering Ron, . Complete biology for Cambridge igcse. New York: Oxford University Press. 2006.