APA (7th ed.) Zitazioa
Trager, E. C. (1956). The PD's: Pronunciation drills for learners of English. ELS Publication.
Chicago Style (17th ed.) Zitazioa
Trager, Edith Crowell. The PD's: Pronunciation Drills for Learners of English. California: ELS Publication, 1956.
MLA (9th ed.) Zitazioa
Trager, Edith Crowell. The PD's: Pronunciation Drills for Learners of English. ELS Publication, 1956.
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