Pili, I. B. (1977). A survey of completed descriptive and contrastive researches on teaching English as a second language from 1959 to 1971 [microform]. Photoduplication Service.University of the Philippines Library.
शिकागो शैली (17वां संस्करण) प्रशस्ति पत्रPili, Irene B. A Survey of Completed Descriptive and Contrastive Researches on Teaching English as a Second Language from 1959 to 1971 [microform]. Quezon City: Photoduplication Service.University of the Philippines Library, 1977.
एमएलए (9वां संस्करण) प्रशस्ति पत्रPili, Irene B. A Survey of Completed Descriptive and Contrastive Researches on Teaching English as a Second Language from 1959 to 1971 [microform]. Photoduplication Service.University of the Philippines Library, 1977.
चेतावनी: ये उद्धरण हमेशा 100% सटीक नहीं हो सकते हैं.