Cita APA (7th ed.)

O'Neill, R. (1994). Longman english works: Students' book. Longman.

Cita Chicago (17th ed.)

O'Neill, Robert. Longman English Works: Students' Book. Madrid: Longman, 1994.

Cita MLA (9th ed.)

O'Neill, Robert. Longman English Works: Students' Book. Longman, 1994.