Cita APA (7th ed.)

ECKERSLEY, C. (1956). Essential English for foreign students. Longman.

Cita Chicago (17th ed.)

ECKERSLEY, C.E. Essential English for Foreign Students. London: Longman, 1956.

Cita MLA (9th ed.)

ECKERSLEY, C.E. Essential English for Foreign Students. Longman, 1956.