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Dyfyniad Arddull ChicagoPili, Irene B. A Survey of Completed Descriptive and Contrastive Researches on Teaching English as a Second Language from 1959 to 1971. [Quezon City: s.n.], 1973.
Dyfyniad MLAPili, Irene B. A Survey of Completed Descriptive and Contrastive Researches on Teaching English as a Second Language from 1959 to 1971. s.n.], 1973.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.