National Development Group for Educational Innovation & Sumagaysay, L. S. (1980). In-service education for primary teachers: Design formulation. National Development Group for Educational Innovation.
शिकागो शैली (17वां संस्करण) प्रशस्ति पत्रNational Development Group for Educational Innovation और Lourdes S. Sumagaysay. In-service Education for Primary Teachers: Design Formulation. Manila: National Development Group for Educational Innovation, 1980.
एमएलए (9वां संस्करण) प्रशस्ति पत्रNational Development Group for Educational Innovation और Lourdes S. Sumagaysay. In-service Education for Primary Teachers: Design Formulation. National Development Group for Educational Innovation, 1980.
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