APA (7th ed.) Zitazioa

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

Chicago Style (17th ed.) Zitazioa

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

MLA (9th ed.) Zitazioa

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