Cita APA (7a ed.)

Kingsbury, R., & Wellman, G. (1987). Longman advanced english. Longman.

Cita Chicago Style (17a ed.)

Kingsbury, Roy, y Guy Wellman. Longman Advanced English. Essex, England: Longman, 1987.

Cita MLA (8a ed.)

Kingsbury, Roy, y Guy Wellman. Longman Advanced English. Longman, 1987.