Cita APA (7a ed.)

Elsworth, S. (1991). Discoveries. Activity book 1. Longman.

Cita Chicago Style (17a ed.)

Elsworth, Steve. Discoveries. Activity Book 1. Essex: Longman, 1991.

Cita MLA (9a ed.)

Elsworth, Steve. Discoveries. Activity Book 1. Longman, 1991.