Cita APA (7th ed.)

GRAVER, B. (1971). Advanced english practice (2nd ed.). O.U.P.

Cita Chicago (17th ed.)

GRAVER, B.D. Advanced English Practice. 2nd ed. London: O.U.P, 1971.

Cita MLA (9th ed.)

GRAVER, B.D. Advanced English Practice. 2nd ed. O.U.P, 1971.