APA

Collier Macmillan Internacional, . (1981). New english 900: Book 1. New York: Collier Macmillan Internacional.

Chicago

Collier Macmillan Internacional, . 1981. New english 900: Book 1. New York: Collier Macmillan Internacional.

Harvard

Collier Macmillan Internacional, . (1981). New english 900: Book 1. New York: Collier Macmillan Internacional.

MLA

Collier Macmillan Internacional, . New english 900: Book 1. New York: Collier Macmillan Internacional. 1981.