Cita APA (7a ed.)

Kingsbury, R., & Spratt, M. (1994). Longman proficiency skills: Teacher's guide (1st pub., 8th impr.). Longman.

Cita Chicago Style (17a ed.)

Kingsbury, Roy, y Mary Spratt. Longman Proficiency Skills: Teacher's Guide. 1st pub., 8th impr. Harlow: Longman, 1994.

Cita MLA (9a ed.)

Kingsbury, Roy, y Mary Spratt. Longman Proficiency Skills: Teacher's Guide. 1st pub., 8th impr. Longman, 1994.