Cita APA (7th ed.)

Heath, R. B. (1975). Impact assignments in english (2a. ed.). Longman.

Cita Chicago (17th ed.)

Heath, R. B. Impact Assignments in English. 2a. ed. Londres: Longman, 1975.

Cita MLA (9th ed.)

Heath, R. B. Impact Assignments in English. 2a. ed. Longman, 1975.